21-25 May 2018
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Contribution List

Displaying 134 contributions out of 134
Considering NLSUSY-structure of space-time just inspired by nonlinear representation of SUSY(NLSUSY) and performing the ordinary geometric arguments of Einstein general relativity(GR) principle, we obtain NLSUSY invariant Einstein-Hilbert-type general relativity action(nonlinear supersymmetric general relativity (NLSUSYGR)) equipped with the cosmological term of the robust SUSY breaking encoded in ... More
Presented by Prof. Kazunari SHIMA on 24 May 2018 at 4:50 PM
Session: Plenary Session
String theory suggests the existence of multiple axion-like particles (ALPs) as well as hidden sector gauge bosons. Some of those ALPs and hidden U(1) gauge bosons (dark photons) might be light enough to result in interesting astrophysical and/or cosmological consequences. As an example of such possibility, we examine ALP-driven late time magnetogenesis generating the cosmic magnetic field via the ... More
Presented by Kiwoon CHOI on 21 May 2018 at 11:00 AM
In Peccei-Quinn (PQ) solutions to the strong CP problem, a global $U(1)_{PQ}$ symmetry is typically added by hand. However, $U(1)_{PQ}$ need not be exact: it may arise from discrete symmetry, provided the PQ solution is protected to sufficient order. We present a rather complete model, based on Pati-Salam unification and $A_4$, wherein such discrete symmetries are the very same symmetries that gov ... More
Presented by Fredrik BJÖRKEROTH on 23 May 2018 at 3:20 PM
It has been recently argued that the presence of any non-SUSY AdS stable vacua implies that a theory can not be consistently coupled to gravity (Ooguri-Vafa conjecture). In particular, this can be applied to the SM and its compactifications to 3 or 2 dimensions to obtain predictions on low energy physics. We will review some implications from these compactifications in general and present in detai ... More
Presented by Alvaro HERRAEZ on 23 May 2018 at 3:00 PM
Beside neutrino masses, an assortment of precision observables probe new physics in the lepton sector. Experimental anomalies include a 3.5-sigma discrepancy in the anomalous magnetic moment of the muon and a 4-sigma indication of lepton universality violation in B-meson semi-leptonic decays. Effective field theory is a useful framework for studying observables sensitive to multi-TeV scales in a m ... More
Presented by Rupert COY on 23 May 2018 at 4:10 PM
Session: Plenary Session
While the LHC has done an excellent job of looking for new physics in all the expected places using simplified models, so far much less attention has been paid to model-independent, data-driven approaches. I will review a recently proposed method of "rectangular aggregations" that can find potentially interesting excesses in existing LHC searches without relying on simplified models. As a proof of ... More
Presented by David SHIH on 21 May 2018 at 12:00 PM
I will discuss the asymptotic-safety paradigm as a framework for model of quantum gravity and matter at and beyond the Planck scale. I will highlight indications for the theoretical viability of this scenario and discuss how in this setting, Planck-scale physics could lead to testable consequences at the electroweak scale. In particular, the asymptotic-safety paradigm could have a higher predictiv ... More
Presented by Astrid EICHHORN on 24 May 2018 at 2:00 PM
We use Pauli-Villars regularization to evaluate the conformal and chiral anomalies in the effective field theories from Z3 and Z7 compactifications of the heterotic string without Wilson lines. We show that parameters for Pauli-Villars chiral multiplets can be chosen in such a way that the anomaly is universal in the sense that its coefficient depends only on a single holomorphic function of the t ... More
Presented by Jacob LEEDOM on 23 May 2018 at 2:40 PM
Twin Higgs (TH) models explain the absence of new colored particles responsible for natural electroweak symmetry breaking. All known ultraviolet completions of TH models require some non-perturbative dynamics below the Planck scale. A new type of supersymmetric Twin Higgs model is presented in which the TH mechanism is introduced by a new asymptotically free gauge symmetry. The model features natu ... More
Presented by Marcin BADZIAK on 22 May 2018 at 3:50 PM
Non-supersymmetric Grand Unified SO(10) × U(1)PQ models have all the ingredients to solve several fundamental problems of particle physics and cosmology — neutrino masses and mixing, baryogenesis, the non-observation of strong CP violation, dark matter, inflation — in one stroke. The axion — the pseudo Nambu-Goldstone boson arising from the spontaneous breaking of the U(1)PQ Peccei-Quinn sy ... More
Presented by Anne ERNST on 24 May 2018 at 2:00 PM
We propose a ``Light Shining Through Walls"-type experiment to search for axions with high-$Q$ superconducting RF cavities. Our setup uses a gapped toroid to confine a static magnetic field, with production and detection cavities positioned in regions of vanishing external field. We argue that the confining toroid does not significantly screen the axion-induced signal for frequencies of order the ... More
Presented by Vijay NARAYAN on 22 May 2018 at 2:20 PM
The axion solution to the strong CP problem also provides a natural dark matter candidate. If the PQ symmetry has ever been restored after inflation, topological defects of the axion field would have formed and produced relic axions, whose abundance is in principle calculable. Using numerical simulations I will present a detailed study of the evolution of axion strings and the resulting spectrum o ... More
Presented by Marco GORGHETTO on 23 May 2018 at 2:20 PM
I will present QCD axion or cosmological Goldstone bosons, such as ultra-light dark matter or quintessence, in a model with global symmetry highly protected by gauge symmetries. The global symmetry is accidental, obtained from an abelian quiver with scalar bifundamental fields. The Goldstone boson mass may receive explicit breaking contributions, but these are already much suppressed for a few qui ... More
Presented by Quentin BONNEFOY on 23 May 2018 at 2:40 PM
Chiral electroweak anomalies predict fermion interactions that violate baryon (B) and lepton number (L), and can be dressed with large numbers of Higgs and gauge bosons. The estimation of the total B+L violating rate from an initial two-particle state --potentially observable at colliders-- has been the subject of an intense discussion, mainly centered on the resummation of boson emission, which i ... More
Presented by Carlos TAMARIT
Chiral electroweak anomalies predict fermion interactions that violate baryon (B) and lepton number (L), and can be dressed with large numbers of Higgs and gauge bosons. The estimation of the total B+L violating rate from an initial two-particle state --potentially observable at colliders-- has been the subject of an intense discussion, mainly centered on the resummation of boson emission, which i ... More
Presented by Carlos TAMARIT on 22 May 2018 at 2:40 PM
We study constraints from Big Bang Nucleosynthesis on inert particles in a dark sector which contribute to the Hubble rate and therefore change the predictions of the primordial nuclear abundances. We pay special attention to the case of MeV-scale particles decaying into dark radiation, which are neither fully relativistic nor non-relativistic during all temperatures relevant to Big Bang Nucleosyn ... More
Presented by Marco HUFNAGEL on 23 May 2018 at 4:30 PM
Dynamical relaxation in an interesting framework in which the scale of new physics is pushed far beyond the observable range without abandoning the principles of naturalness. A low value of the electroweak scale originates from a dynamical selection process that comes from an interaction between the Higgs boson and an axion-like particle (a relaxion). During the relaxation, the relaxion rolls down ... More
Presented by Adam MARKIEWICZ on 23 May 2018 at 4:50 PM
One of the key motivations for supersymmetric (SUSY) models is their ability to naturally stabilize the electroweak scale and so address the hierarchy problem. However, in the Minimal Supersymmetric Standard Model (MSSM) accommodating a 125 GeV Higgs boson appears to once again require a degree of fine-tuning. This has fueled interest in non-minimal SUSY models, such as the Next-to-MSSM (NMSSM), t ... More
Presented by Dylan HARRIES on 24 May 2018 at 5:10 PM
Session: Review Talk
Recently, machine learning techniques have entered the field of string phenomenology, for example, in order to identify promising string models in the vast landscape of string theory vacua. We review different approaches and techniques, like 'Autoencoders', 'Reinforcement Learning' and 'Generative Adversarial Networks' and apply them to several physical questions.
Presented by Mr. Patrick VAUDREVANGE on 24 May 2018 at 9:00 AM
The latest Planck CMB data seem to strongly constrain the Hot Dark Matter scenarios, although they stay in tension with direct Hubble constant measurements. One can expect that in near future the experimental uncertainly for the effective number of neutrino species N_{eff} will shrink vastly. Therefore, in order to estimate the allowed parameter space of models predicting a Hot Dark Matter compone ... More
Presented by Paweł SZCZERBIAK on 23 May 2018 at 4:50 PM
Session: Plenary Session
Presented by Stefan POKORSKI on 23 May 2018 at 12:00 PM
Many models of Beyond the Standard Model physics contain particles that are charged under both Standard Model and Hidden Valley gauge groups, yet very little effort has been put into establishing their experimental signatures. We provide a general overview of the collider phenomenology of spin 0 or 1/2 mediators with non-trivial gauge numbers under both the Standard Model and a single new confinin ... More
Presented by Hugues BEAUCHESNE on 23 May 2018 at 3:00 PM
A massless quark solution to the Strong CP problem is implemented with an extra confining gauge group that is unified with the SM QCD group in a CUT (Colour Unified Theory). A novel contribution to the axion mass (due to the small-size instantons at the CUT breaking scale) renders the dynamical axion heavy. This allows to protect the PQ symmetry from semi-classical gravitational effects that could ... More
Presented by Pablo QUÍLEZ LASANTA on 23 May 2018 at 3:00 PM
Many Standard Model extensions that address the hierarchy problem contain Dirac-fermion partners of the top quark, which are typically expected around the TeV scale. Searches for these vector-like quarks mostly focus on their decay into electroweak gauge bosons or Higgs plus a standard model quark. In this talk, backed by models of composite Higgs, we propose a set of simplified scenarios that inc ... More
Presented by Dr. Thomas FLACKE on 23 May 2018 at 5:10 PM
Session: Plenary Session
We consider a composite model where both the Higgs and a complex scalar χ, which is the dark matter (DM) candidate, arise as light pseudo Nambu-Goldstone bosons (pNGBs) from a strongly coupled sector with TeV scale confinement.
Presented by Andreas WEILER on 21 May 2018 at 3:30 PM
Composite Higgs models are among the most promising alternatives to solve the hierarchy problem and provide a dynamical mechanism to break the electroweak symmetry. In this talk I will discuss some predictions of specific UV realizations of such scenario. I will analyze in particular the phenomenology of vector and scalar states in a SU(4)/Sp(4) symmetry breaking pattern, using lattice results as ... More
Presented by Dr. Diogo BUARQUE FRANZOSI on 22 May 2018 at 4:10 PM
A light bosonic field mediates a long-range "fifth" force between objects. If the field has self-interactions, experimental constraints on such forces are weakened due to a screening effect. We study how technically natural values for self-interaction terms in the field's potential lead to modification of existing constraints. We show that under this assumption of natural self-interactions, existi ... More
Presented by Sebastian ELLIS
We investigate the bounds which can be placed on generic new-physics contributions to dijet production at the LHC using the framework of the Standard Model Effective Field Theory, deriving the first consistently-treated EFT bounds from non-resonant high-energy data. In order to reach consistent, model-independent EFT conclusions, it is necessary truncate the EFT effects consistently at the first n ... More
Presented by Stefan ALTE on 22 May 2018 at 4:10 PM
Since the LHC has not provided us with any hints towards new physics, it is ever more interesting to constrain BSM theories from purely theoretical considerations. Requiring that the electroweak vacuum in any BSM model is at least metastable, can lead to stringent constraints on the parameter space of the model. Many popular extensions of the SM, such as supersymmetry, feature greatly extended sca ... More
Presented by Mr. Jonas WITTBRODT on 24 May 2018 at 4:30 PM
We demonstrate that rotational superradiance can be efficient in millisecond pulsars. Measurements from the two fastest known pulsars PSR J1748-2446ad and PSR B1937+21 can place bounds on bosons with masses below 10^-11 eV. The bounds are maximally good at masses corresponding to the rotation rate of the star, where scalar interactions that mediate forces ∼ 10^7 times weaker than gravity are rul ... More
Presented by Paul RIGGINS on 22 May 2018 at 3:50 PM
The relaxion models propose a new idea to explain the smallness of the Higgs mass. They rely on the scanning of the Higgs mass parameter by a new field, the relaxion, and a back-reaction mechanism that is triggered when Higgs vacuum expectation value has reached the size of the electroweak scale, making the relaxion evolution cease. In the usual relaxion model the scanning happens during an inflat ... More
Presented by Nayara FONSECA on 23 May 2018 at 4:10 PM
We investigate dark matter (DM) production in an early matter dominated era where a heavy long-lived particle decays to radiation and DM. In addition to DM annihilation into and thermal DM production from radiation, we include direct DM production from the decay of the long-lived particle.
Presented by Mr. Fazlollah HAJKARIM on 23 May 2018 at 5:10 PM
Session: Plenary Session
Weakly Interacting Massive Particles (WIMPs) have been the target of cosmic ray experiments for decades. AMS-02 is the first experiment which can realistically probe WIMP annihilation signals in the antiproton channel. Due to the tiny experimental errors, uncertainties in the astrophysical background have become the most limiting factor for the dark matter detection. I will use the combinatio ... More
Presented by Dr. Martin WINKLER on 25 May 2018 at 11:30 AM
We study simplified models of top-flavoured dark matter in the framework of Dark Minimal Flavour Violation. In this setup the coupling of the dark matter flavour triplet to SM quark triplets constitutes the only new source of flavour and CP violation. The parameter space of the model is restricted by LHC searches with missing energy final states, by neutral meson mixing data, by the observed dark ... More
Presented by Simon KAST on 24 May 2018 at 3:20 PM
The strong direct detection limits indicate that dark matter may not directly couple to quarks and consequently direct detection only occur at loop level. We study direct detection in the prototype example of an electroweak singlet dark matter fermion coupled to an extended dark sector composed of a new fermion and a new scalar. We also discuss the cases if either the new fermion or scalar is a SM ... More
Presented by Michael SCHMIDT on 24 May 2018 at 2:00 PM
Due to its highly suppressed cross section (fermionic) dark matter interacting with the Standard Model via pseudoscalar mediators is expected to be essentially unobservable in direct detection experiments. We consider both a simplified model and a more realistic model based on an extended two Higgs doublet model and compute the leading one-loop contribution to the effective dark matter- nucleon in ... More
Presented by Stefan VOGL on 24 May 2018 at 2:20 PM
Session: Plenary Session
The cosmological standard model, LCDM, provides a very good overall fit to the precision cosmological data from the CMB, its polarization, baryon acoustic oscillations, measurements of large scale structure, and the current expansion rate of the universe. The most significant tension in the fit is associated with two quantities: the current expansion rate, H_0, and the amplitude of the matter powe ... More
Presented by Martin SCHMALTZ on 21 May 2018 at 10:00 AM
We perform a precise calculation of the decay rate of the electroweak vacuum in the standard model as well as in models beyond the standard model. We use a recently developed technique to calculate the decay rate of a false vacuum, which provides a gauge invariant calculation of the decay rate at the one-loop level. We give a prescription to take into account the zero modes in association with tra ... More
Presented by So CHIGUSA on 24 May 2018 at 4:10 PM
Session: Plenary Session
Several intriguing deviations from Standard Model expectations have been observed in flavor-violating processes in the last few years, most notably hints for violation of lepton flavor universality, both in neutral-current B meson decays involving light leptons and in charged-current B meson decays involving tau leptons. I will give an overview of the status of these deviations and discuss possibl ... More
Presented by Dr. David STRAUB on 23 May 2018 at 11:00 AM
The Weinberg operator allows for the construction of radiative Majorana neutrino masses. In this letter, it will be shown that it is possible to construct a one-loop diagram that will be the principal component of the neutrino mass matrix and that will have an exact mixing matrix with θ13=0. The addition of a two-loop diagram, which is naturally suppressed, allows the creation of the correct pert ... More
Presented by Daniel WEGMAN on 24 May 2018 at 3:20 PM
In the absence of new particles at the LHC, the effective field theory framework is appropriated to look for small deviations from the Standard Model (SM). In this case, the leading effect is encoded on the interference term between the SM and dimension-6 operators. However, at the high energy limit due to helicity selection rules, this term, for some operators, is suppressed which leads to an obs ... More
Presented by Rafael AOUDE on 23 May 2018 at 3:20 PM
More than eighty years after they were first proposed, neutrinos still remain an enigma. Although they are an integral part of Standard Model but still we know very little about them. In particular, the Dirac or Majorana nature of neutrinos is still unclear with no clear indication of their nature. However, for a long time, theoretical particle physicists believed that neutrinos must be Majorana i ... More
Presented by Rahul SRIVASTAVA on 24 May 2018 at 2:20 PM
A variety of experiments have been developed over the past decades, aiming at the detection of Weakly Interactive Massive Particles (WIMPs) via their scattering in an instrumented medium. The sensitivity of these experiments has improved with a tremendous speed, thanks to a constant development of detectors and analysis methods. Detectors capable of reconstructing the direction of the nuclear reco ... More
Presented by Prof. A. MURAT GULER
In this talk, I will discuss the EFT approach to LHC physics and Dark Matter searches regarding its validity and prospects to gain information on the underlying UV physics. In particular in the first case, correlations will be pointed out that allow to directly access the mass of new particles beyond collider reach, while in the second case, a new effective description will be presented that allow ... More
Presented by Dr. Florian GOERTZ on 24 May 2018 at 4:10 PM
We study the phenomenology of a Next-to-Minimal Supersymmmetric Standard Model (NMSSM) that can achieve early universe inflation. The Higgs sector of such a model clearly differs from the usual NMSSM and can provide a smoking gun of inflation at low energies.
Presented by Dr. Wolfgang Gregor HOLLIK on 22 May 2018 at 2:40 PM
We propose a new dynamical relaxation mechanism based on a singlet extension of the MSSM. In this scenario, a small enough soft mass of the MSSM singlet is responsible for the electroweak symmetry breaking and the Higgs VEV of order 100 GeV, whereas the effects of a large soft mass parameter of the Higgs boson, −m_{hu}^2 are dynamically compensated by an MSSM singlet field. The smallness of the ... More
Presented by Bumseok KYAE on 24 May 2018 at 4:10 PM
We investigate the electroweak vacuum stability in presence of a scalar dark matter and neutrino mass model through type-I seesaw. The minimal Higgs portal dark matter framework is extended here with another scalar singlet field carrying non-zero vacuum expectation value. Our results reveal that inclusion of this extra scalar not only helps in achieving absolute vacuum stability (even with large n ... More
Presented by Dr. ARUNANSU SIL on 24 May 2018 at 5:10 PM
It is known that in the absence of a gauge singlet field, a specific class of supersymmetry (SUSY) breaking non-holomorphic (NH) terms can be soft breaking in nature so that they may be considered along with the Minimal Supersymmetric Standard Model (MSSM) and beyond. There have been studies related to these terms in minimal supergravity based models. Consideration of an F-type SUSY breaking scena ... More
Presented by Samadrita MUKHERJEE on 24 May 2018 at 4:30 PM
It is important to understand not only the observational constraints on large field inflation, but also any possible theoretical constraints. Among the theoretical constraints, one could focus one's attention to Ultra-Violet (UV) sensitivity. In this talk, I shall present simple variations of the minimal extranatural inflation model of inflation which are completely consistent with CMB observation ... More
Presented by Dr. Gaurav GOSWAMI
We point out that the stringent lower bounds on the masses of additional electrically neutral and charged Higgs bosons crucially depend on the flavour structure of their Yukawa interactions. We show that these bounds can easily be evaded by the introduction of flavour-changing neutral currents in the Higgs sector. As an illustration, we study the phenomenology of a two Higgs doublet model with a Y ... More
Presented by Dr. Ayan PAUL on 23 May 2018 at 2:20 PM
Session: Review Talk
Several observables in flavour physics deviate from their Standard-Model (SM) expectation. The most prominent ones are related to the decay $b\to s \mu^+ \mu^-$, with a combined statistical significance well above 4 standard deviations. Similarly, branching fractions of $b \to c \tau \nu$ decays and the direct CP asymmetry in $K\to \pi \pi$ decays exceed the SM expectation. I'll discuss theoretica ... More
Presented by Prof. Ulrich NIERSTE on 23 May 2018 at 9:00 AM
The models with the gauge group $SU(3)_c\times SU(3)_L\times U(1)_X$ (331-models) have been advocated to explain why there are three fermion generations in Nature. As such they provide partial understanding of the flavour sector. The hierarchy of fermion masses in the Standard Model is another puzzle which remains without compelling explanation. In this talk I present a model that incorporates Fro ... More
Presented by Niko KOIVUNEN on 23 May 2018 at 5:10 PM
Session: Plenary Session
For most string vacua, only the chiral matter spectrum can be computed in terms of topological data of the compact extra dimensions, while already the vector-like spectrum remains elusive. If the compact extra dimensions consist of (orbifolds of) tori, however, the string quantisation can be explicitly performed and thus not only the full tower of massless and massive matter states can be computed ... More
Presented by Prof. Gabriele HONECKER on 24 May 2018 at 12:00 PM
In the near future, fundamental interactions at high-energy scales may be most efficiently studied via precision measurements at low energies. In this talk I will discuss the possible impact of the DUNE neutrino experiment on constraining the SM Effective Field Theory. The unprecedented neutrino flux offers an opportunity to greatly improve the current limits via precision measurements of the trid ... More
Presented by Giovanni GRILLI DI CORTONA on 23 May 2018 at 4:30 PM
I show how generating hierarchy via the clockwork mechanism can be generalized in various directions including nonabelian global groups, supergravity and Susy breaking.
Presented by Dr. Ido BEN-DAYAN on 23 May 2018 at 5:10 PM
Session: Plenary Session
I will discuss phase transitions at the TeV scale, in particular the electroweak one (in extensions of the standard model). I will review the current status of how gravitational waves are generated during the phase transition, and show how the resulting gravitational wave signal can be computed from key properties of the transition. Finally, I will discuss detection prospects at future interferom ... More
Presented by Stephan HUBER on 25 May 2018 at 10:00 AM
Heavy neutral leptons or massive sterile neutrinos are present in many well-motivated beyond the Standard Model theories, sometimes being accesible at present colliders. Our aim is to discuss the potential of the LHC to produce and discover this kind of new particles when their masses are in the GeV range. Moreover, and depending on their masses and couplings, they can be long-lived and lead to si ... More
Presented by Dr. Xabier MARCANO
Heavy neutral leptons or massive sterile neutrinos are present in many well-motivated beyond the Standard Model theories, sometimes being accesible at present colliders. Our aim is to discuss the potential of the LHC to produce and discover this kind of new particles when their masses are in the GeV range. Moreover, and depending on their masses and couplings, they can be long-lived and lead to si ... More
Presented by Dr. Xabier MARCANO on 22 May 2018 at 2:00 PM
Long-lived light particles (LLLPs) appear in many extensions of the standard model. LLLPs are usually motivated by the observed small neutrino masses, by dark matter or both. Typical examples for fermionic LLLPs (a.k.a. heavy neutral fermions, HNFs) are sterile neutrinos or the lightest neutralino in R-parity violating supersymmetry. The high luminosity LHC is expected to deliver up to 3/ab of dat ... More
Presented by Simon Zeren WANG on 22 May 2018 at 2:20 PM
Session: Plenary Session
With increasingly precise measurements of Higgs boson interactions, we start to set tighter limits on Standard Model extensions. First, I will review the impact of existing and ongoing Higgs coupling measurements on how they constrain such extensions. In the second part of the presentation, I will focus on one of the most important couplings of the scalar sector, the Higgs self-coupling. Given the ... More
Presented by Michael SPANNOWSKY on 22 May 2018 at 10:00 AM
Contrary to common perception, we show that the current Higgs data does not eliminate the possibility of a sequential fourth generation that get their masses through the same Higgs mechanism as the first three generations. The inability to fix the sign of the bottom-quark Yukawa coupling from the available data plays a crucial role in accommodating a chiral fourth generation which is consistent wi ... More
Presented by Ipsita SAHA on 23 May 2018 at 4:30 PM
The decays of neutral Higgs bosons into Standard Model fermions and gauge-bosons in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) are investigated at the full one-loop order with some higher-order QCD corrections. We take mixing effects for the external Higgs particles consistently into account. In the beginning, some formal aspects of our approach are discussed, before we compare our ... More
Presented by Dr. Sebastian PAßEHR on 23 May 2018 at 4:50 PM
The study of the renormalization group improved effective potential of the Standard Model has revealed existence of a local maximum at field strengths of the order of 10^10 GeV. If the Standard Model is valid for very high energy scales, then the possibility of the production of cosmological domain walls in the early Universe occurs. We investigated dynamics of networks of domain walls using latti ... More
Presented by Tomasz KRAJEWSKI on 22 May 2018 at 3:30 PM
I will present a model of a hill-climbing inflation based on a scalar-tensor theory. I will show how the reheating can be generated by gravitational particle production and I will present the consequences of the gravitational reheating on the thermal history of the Universe and primordial gravitational waves.
Presented by Dr. Michal ARTYMOWSKI on 22 May 2018 at 2:00 PM
Minimal scenarios with light (sub-GeV) dark matter are usually accompanied by a correspondingly light "dark sector". We will show that the presence of the latter usually leads to strong bounds from cosmology and bright detection prospects at fixed target experiments and colliders.
Presented by Mr. Luc DARMÉ on 23 May 2018 at 5:30 PM
We study the capabilities of IceCube to search for sterile neutrinos with masses above 10 eV by analyzing its νμ disappearance atmospheric neutrino sample. We find that IceCube is not only sensitive to the mixing of sterile neutrinos to muon neutrinos, but also to the more elusive mixing with tau neutrinos through matter effects. The currently released 1-year data shows a mild (around 2σ) prefe ... More
Presented by Julia GEHRLEIN on 22 May 2018 at 2:00 PM
Session: Plenary Session
BSM models must be confronted with a series of experimental and theoretical constraints. On the theoretical side, it is standard to check the tree-level vacuum stability, the tree-level perturbative unitarity constraints in the limit of large scattering energies, and the cut-off scale using one-loop running with tree-level matching. I will discuss that these constraints can get crucial corrections ... More
Presented by Dr. Florian STAUB on 21 May 2018 at 3:00 PM
Many composite Higgs models predict the existence of vector-like quarks with masses outside the reach of the LHC, e.g. mQ > 2 TeV, in particular if these models contain a dark matter candidate. In such models the mass of the new resonances is bounded from above to satisfy the constraint from the observed relic density. We therefore develop new strategies to search for vector-like quarks at a futur ... More
Presented by Dr. Mikael CHALA on 24 May 2018 at 5:10 PM
Planck scale acts as a threshold where a new description of spacetime is expected to appear. We consider the invariant Planck scale modified/deformed Poincare algebra proposed by Magueijo and Smolin and study the consequences as the Planck scale corrections to the known physics. We get Planck scale modified dispersion relation and an effective invariant ultraviolet energy cut-off (Planck energy). ... More
Presented by Dheeraj Kumar MISHRA
Probably not. I will introduce some different gravity theories which are as good as GR in the sense that all of constraints are first class and therefore a graviton has only 2 polarisations and the structure of the theory at low energies is thus expected to be stable against quantum corrections.
Presented by Chunshan LIN
Session: Plenary Session
Presented by Dr. Jong Soo KIM on 22 May 2018 at 11:00 AM
A compelling mechanism for leptogenesis consists into CP-violating oscillations of mass-degenerate pairs of sterile neutrinos with masses lying at the GeV scale. This kind of setup finds a natural embedding in models like the Inverse See-Saw, where the mass degeneracy of these neutrino pairs is associated to a small violation of the lepton number. We present the resulst of a systematic study based ... More
Presented by Dr. Giorgio ARCADI on 23 May 2018 at 2:00 PM
In this work, we consider a model in which the SM is extended by a lepton number gauge group $U(1)_L$. The arising gauge anomalies are canceled by adding two sets of SM vector-like leptons. We further add a scalar field that spontaneously breaks $U(1)_L$. A residual global symmetry ensures the stability of the lightest additional lepton, thus providing a dark matter candidate. We investigate curre ... More
Presented by Eric MADGE on 24 May 2018 at 4:50 PM
The cosmic ray electron + positron flux measured recently by the DAMPE experiment up to 5 TeV has gained great attention. So far, the interpretations focuss on the spectral softening around 0.9 TeV and on a small fluctuation of one data point at 1.4 TeV. We want to point at three additional features that can be found in the data by separating the primary and the seconary compontent of the cosmic r ... More
Presented by Ms. Annika REINERT on 24 May 2018 at 4:10 PM
Session: Plenary Session
It has been conjectured that in theories consistent with quantum gravity infinite distances in field space coincide with an infinite tower of states becoming massless exponentially fast. In this talk I present non-trivial evidence for this conjecture from the study of Type IIB string theory on Calabi-Yau threefolds. I will also comment on the observation that the behavior of the metric and gaug ... More
Presented by Dr. Thomas GRIMM on 24 May 2018 at 11:00 AM
Session: Review Talk
I review theories of dark matter and their detection
Presented by Kathryn ZUREK on 25 May 2018 at 9:00 AM
Standard thermal leptogenesis in the type-I seesaw model requires very heavy right-handed neutrinos (RHNs). This diminishes the prospects of directly testing this scenario in experiments and, thus, motivates efforts to construct models that generate the baryon asymmetry of the Universe at a lower RHN mass scale. In this talk, I will discuss two such alternative scenarios: First, I will revisit Ern ... More
Presented by Dr. Kai SCHMITZ on 23 May 2018 at 2:20 PM
Mechanisms that yield mass degeneracies in extended Higgs sectors with multiple Higgs doublets are examined. Some puzzling features of a recent 3HDM constructed by Ivanov and Silav are considered that appear to be connected to the mass degeneracies of their model.
Presented by Prof. Howard HABER on 22 May 2018 at 2:00 PM
A massive particle charged under the electroweak gauge symmetry is one of the best candidate of the dark matter and called "Minimal dark matter." In this talk, I will discuss new strategies for such a dark matter hunting at collider, using precision measurements of the standard processes.
Presented by Satoshi SHIRAI on 24 May 2018 at 4:30 PM
Session: Review Talk
I will give my impressions of model building in the LHC era. WHAT are the problems for theory, WHERE are the hints for new physics and WHEN will we know.
Presented by Stuart RABY on 21 May 2018 at 9:00 AM
I will talk about popular scalar extensions of the Standard Model, namely the singlet extension, the 2-Higgs doublet model (2HDM) and its extension by a singlet scalar. I will focus on the contributions of the added scalars to the anomalous magnetic moment of the muon, and the electric dipole moment of the electron in these models.
Presented by Dr. Venus KEUS on 22 May 2018 at 2:20 PM
The absence of new physics in current LHC searches leads to increasing interest in a variety of non-minimal extensions of the Standard Model (SM). Also the scale of new physics in widely studied models is pushed to higher energies. Automation tools such as SARAH allow for comprehensive studies of a wider class of models beyond the Standard Model (SM). Not only the tree-level values but also NLO an ... More
Presented by Martin GABELMANN on 22 May 2018 at 3:50 PM
Session: Plenary Session
I review how natural SUSY may emerge from the string landscape and present probability distributions for Higgs and sparticle masses
Presented by Prof. Howard Baer BAER on 22 May 2018 at 11:30 AM
We consider an extension of the Standard Model by right-handed neutrinos and we argue that, under plausible assumptions, a neutrino mass of O(0.1) eV is naturally generated by the breaking of the lepton number at the Planck scale, possibly by gravitational effects, without the necessity of introducing new mass scales in the model. Some implications of this framework are also briefly discussed.
Presented by Dr. Takashi TOMA on 24 May 2018 at 2:00 PM
Session: Plenary Session
b->c cbar s transitions proceed at the tree-level in the weak interactions in the Standard Model, and for this reason are typically ignored in the search for new physics. I will show that, in fact, even small BSM contributions can give observables effects in B-meson lifetime observables, CP-violation measurements, as well as rare and radiative decays. This can provide useful constraints on or poss ... More
Presented by Sebastian JAEGER on 23 May 2018 at 10:00 AM
Session: Plenary Session
The astrophysical evidence for dark matter suggests that the standard model should be supplemented by a dark sector, containing a particle dark matter candidate. In my talk I will give give an overview of new experimental signatures of non-minimal dark sectors with new interactions, in particular: emerging jets from QCD-like dark sectors at colliders, flavour violating signatures of dark pions in ... More
Presented by Pedro SCHWALLER on 25 May 2018 at 12:00 PM
Session: Plenary Session
I will discuss experimental and observational signatures of dark matter with mass at and very well below the MeV scale. The first signature regards dark matter decay into dark radiation states. I will comment on the experimental detectability of dark radiation, and further show that 21 cm astronomy becomes a probe of very light dark radiation; an explanation of the EDGES result is offered. The sec ... More
Presented by Josef PRADLER on 25 May 2018 at 3:00 PM
A very important and promizing direction of reasearch is finding better ways of testing Standard Model and New Physics using Effective Field Theory approach and exploiting precision measurements. In this framework, Electroweak Triple Gauge Couplings play a special role, particularly within diboson production processes. However, there is often a cancellation in the inclusive measurements of the for ... More
Presented by Elena VENTURINI on 23 May 2018 at 2:00 PM
Session: Plenary Session
I will describe recent results on phenomenological consequences of imposing an exotic CP-symmetry of order 4 in multi-Higgs models. Despite minimality of the assumptions, such models have well shaped scalar and flavor sectors and lead to rich phenomenology to be tested in experiments and astroparticle observations.
Presented by Dr. Igor IVANOV on 21 May 2018 at 2:30 PM
Recently there has been revival of interest in partially composite Higgs models, where electroweak symmetry breaking is dynamically induced, and the Higgs boson is a mixture of a composite and an elementary state. While the Goldstone nature of the composite sector explains the lightness of the Higgs, the elementary scalars provide an UV completion for the SM fermion mass generation via traditional ... More
Presented by Dr. Tommi ALANNE on 22 May 2018 at 3:30 PM
We propose a new non-thermal Leptogenesis mechanism that takes place during the reheating epoch, and utilizes the Ratchet mechanism. The interplay between the oscillation of the inflaton during reheating and a scalar lepton leads to a dynamical system that emulates the well-known forced pendulum. This is found to produce driven motion in the phase of the scalar lepton which leads to the generation ... More
Presented by Neil BARRIE on 23 May 2018 at 3:20 PM
Session: Plenary Session
The luminosity upgrade of the LHC (HL-LHC) is being actively pursued with the targeted integrated luminosity of 3 ab-1 by the year of 2037. There has been increasing interest to upgrade the energy of the LHC (HE-LHC) to about a c.m. energy of 27 TeV by doubling the magnetic field in the same tunnel, which is part of the effort of the European Strategy of Particle Physics led by CERN. I present a f ... More
Presented by Tao HAN on 25 May 2018 at 3:30 PM
Grand Unified Theories predict the proton to be unstable and if a particular model is considered, the partial proton decay widths can be calculated. Most often, however, a renormalizable setting is considered and the effective operators possibly describing the physics at the Planck scale are not taken into account. It is well known that one of such effective operators involving the unification gau ... More
Presented by Helena KOLESOVA on 24 May 2018 at 2:40 PM
Session: Plenary Session
A second order pole in the scalar kinetic term can lead to a class of inflation models with universal predictions referred to as pole inflation or α-attractors. While this kinetic structure is ubiquitous in supergravity effective field theories, realising a consistent UV complete model in e.g. string theory is a non-trivial task. For one, one expects quantum corrections arising in the vicinity o ... More
Presented by Alexander WESTPHAL on 24 May 2018 at 11:30 AM
The Littlest Seesaw model based on two right-handed neutrinos with constrained Yukawa couplings provides a highly predictive description of neutrino masses and PMNS mixing parameters. If realised at high energies there will be renormalisation group corrections to the low energy predictions, which depend on the right-handed neutrino masses. We perform a chi squared analysis to determine the right-h ... More
Presented by Sam ROWLEY on 23 May 2018 at 3:00 PM
In this talk I will present the projected sensitivities of upcoming pulsar timing arrays (PTAs) to gravitational waves produced by first-order phase transitions. In contrast to ground- or space-based detectors these experiments are sensitive to phase transitions that occur around keV to MeV energy scales. Consequently, they are excellent probes of many types of light new physics contributing to no ... More
Presented by Toby OPFERKUCH on 22 May 2018 at 3:30 PM
3 topics appeared in the description of processes with unstable particles. 1. Plane wave formalism is insufficient for some realistic problems. The wave packets formalism become necessary. Illustration:The t--channel singularity in small angle scattering. 2. Perturbation series become invalid like in the case of infrared divergence in QED, but in more strong form. Illustration: The s--channel sing ... More
Presented by Prof. Ilya GINZBURG on 23 May 2018 at 5:30 PM
The minimal renormalizable SO(10) Higgs model in which the unified symmetry is broken down by the adjoint representation is known to suffer from tachyonic instabilities along all potentially realistic symmetry-breaking chains. Few years ago, this issue has been identified as a mere relic of the tree level calculations and the radiative corrections to the masses of the pair of the “most dangerous ... More
Presented by Katerina JARKOVSKA on 24 May 2018 at 3:20 PM
The QCD axion is a good dark matter candidate. The observed dark matter abundance can arise from misalignment or defect mechanisms, which generically require an axion decay constant fa ~ O(10^11) GeV (or higher). We introduce a new cosmological origin for axion dark matter, parametric resonance from oscillations of the Peccei-Quinn symmetry breaking field, that requires fa ~ (10^8 − 10^11) GeV. ... More
Presented by Dr. Keisuke HARIGAYA on 23 May 2018 at 2:00 PM
Session: Plenary Session
Consistency with quantum gravity can have significant consequences on low energy physics. Interestingly, it seems that not every effective field theory can be consistently coupled to quantum gravity unless it satifies some additional consistency constraints. Recently substantial effort has been dedicated to determine these constraints in terms of black-hole physics and string theory. Some proposal ... More
Presented by Ms. Irene VALENZUELA on 24 May 2018 at 10:00 AM
Asymptotic safety provides a framework for a UV-complete model of quantum gravity and matter. Within this framework, Renormalization Group flows allow to connect Planck-scale physics to the electroweak scale. I will present indications that asymptotically safe quantum gravity uniquely determines the top Yukawa coupling, resulting in a “retrodiction” of the top-quark mass close to its experimen ... More
Presented by Aaron HELD on 24 May 2018 at 2:40 PM
In this talk a new method or renormalisation-group (RG) improvement of effective potentials in models with extended scalar sector is presented. With the use of this method, the RG improved potential can be expressed as the tree-level potential evaluated at a suitably chosen field-dependent scale. This follows from solving the RG equation for the effective potential with a suitably chosen boundary ... More
Presented by Bogumila SWIEZEWSKA on 24 May 2018 at 4:50 PM
The recently claimed anomaly in the measurement of the 21 cm hydrogen absorption signal by EDGES at redshift z = 17, if cosmological, requires the existence of new physics. The possible attempts to resolve the anomaly rely on either (i) cooling the hydrogen gas via new dark matter-hydrogen interactions or (ii) modifying the soft photon background beyond the standard CMB (suggested by the ARCADE 2 ... More
Presented by Kristjan KANNIKE on 24 May 2018 at 4:30 PM
Session: Plenary Session
Presented by Tien-Tien YU on 25 May 2018 at 2:30 PM
I will describe a version of the dimensional regularization of a classically scale invariant theory, motivated by the requirement to preserve scale invariance at the level of loop corrections. The theory is embedded in a nonrenormalizable Lagrangian, where both the dimensionful regulator \mu and suppression scale of higher-dimensional interactions are interpreted as a vev of a new dynamical scalar ... More
Presented by Pawel OLSZEWSKI on 22 May 2018 at 4:10 PM
I discuss a scenario in which the relaxion field, whose evolution in the early universe is responsible for the smallness of EW scale compared to the cutoff of the theory, also constitutes the Dark Matter of the Universe.
Presented by Enrico MORGANTE on 23 May 2018 at 4:30 PM
Dark matter coupled to light mediators has been invoked to resolve the putative discrepancies between collisionless cold DM and galactic structure observations. However, $\gamma$-ray searches and the CMB strongly constrain such scenarios. To ease the tension, we consider asymmetric DM. We show that, contrary to the common lore, detectable annihilations occur even for large asymmetries, and derive ... More
Presented by Dr. Iason BALDES on 24 May 2018 at 3:00 PM
We study Z′ models arising from SO(10)SO(10), focussing in particular on the gauge group of SU(3)C×SU(2)L×U(1)R×U(1)B−L, broken at the TeV scale to the Standard Model gauge group. This gauge group is well motivated from SO(10) breaking and allows neutrino mass via the linear seesaw mechanism. Assuming supersymmetry, we consider single step gauge unification to predict the gauge couplings, t ... More
Presented by Mr. Simon KING on 24 May 2018 at 3:00 PM
The understanding of flavor and the strong CP problem could be closely related. Motivated by the idea of Comprehensive Unification of elementary particle forces and families, we propose a minimal SO(3) flavor extension of the of the Standard Model which accounts for the observed fermion mass hierarchies, and provides a dynamical understanding of quark mixing and CP violation.
Presented by Mario REIG on 23 May 2018 at 4:50 PM
Session: Plenary Session
The saxion - the modulus of the Peccei-Quinn scalar - or a mixture of it with the modulus of the Higgs - represents a viable inflaton candidate, if one takes into account the possible non-minimal coupling of the PQ scalar to gravity. Remarkably, reheating in saxion/Higgs inflation inevitably restores the PQ symmetry and results therefore in a lower bound on the axion mass around 30 micro-eV. O ... More
Presented by Andreas RINGWALD on 25 May 2018 at 2:00 PM
Session: Plenary Session
Presented by Dr. Nishita DESAI on 22 May 2018 at 12:00 PM
The electroweak symmetry breaking (EWSB) sector still keeps some mysteries under the sleeve. Questions such as what is the dynamical origin of EWSB, what is the true nature of the Higgs boson or are the properties of this particle the ones predicted in the SM remain unanswered. The LHC is our tool to unveil these mysteries and vector boson scattering (VBS) is the perfect window to access them. In ... More
Presented by Claudia GARCIA-GARCIA on 22 May 2018 at 3:30 PM
We describe the many pathways to generate Majorana and Dirac neutrino mass through generalized dimension-5 operators a la Weinberg. The presence of new scalars beyond the Standard Model Higgs doublet implies new possible field contractions, which are required in the case of Dirac neutrinos. We also notice that, in the Dirac neutrino case, the extra symmetries needed to ensure the Dirac nature of n ... More
Presented by Salvador CENTELLES CHULIÁ on 24 May 2018 at 2:40 PM
Self-interactions of dark matter induced by a MeV-scale vector mediator $Z_\text{D}$ can naturally cure some shortcomings of the standard cold dark matter paradigm at small scales. However, if the vector particle decays into Standard Model states, such a scenario is robustly excluded by constraints from energy injection during CMB. We study to what extent this conclusion can be circumvented if $Z_ ... More
Presented by Mr. Sebastian WILD on 24 May 2018 at 2:40 PM
Session: Plenary Session
We will discuss several phenomenological signatures that can result from particle production during inflation, with a paricular attentions ot models of axion inflation. The signatures include large non-gaussianity and sourced gravitational waves at CMB scales, primordial black holes, and gravitational waves at interferometer scales
Presented by Marco PELOSO on 25 May 2018 at 11:00 AM
Session: Plenary Session
We present a new mechanism for making a scalar parametrically lighter than the UV cutoff utilizing non-linearly realized discrete symmetries. The cancelations occur due to a discrete symmetry that is realized as a shift symmetry on the scalar and as an exchange symmetry on the particles with which the scalar interacts.
Presented by Anson HOOK on 21 May 2018 at 11:30 AM
Session: Review Talk
With the LHC Run II coming to an end and the LHC experiments already preparing for HL-LHC, this talk will review the current status of BSM searches, with particular emphasis on new analysis techniques developed in the recent past and possible implications for the LHC Run III and the long term.
Presented by Maurizio PIERINI on 22 May 2018 at 9:00 AM
Session: Plenary Session
I review the experimental indications in favor of short-baseline neutrino oscillations and I discuss their interpretation in the framework of 3+1 neutrino mixing with a sterile neutrino at the eV scale. I show that the recent results of the NEOS and DANSS reactor neutrino experiments give a new model-independent indication in favor of short-baseline electron antineutrino disappearance, confirming ... More
Presented by Dr. Carlo GIUNTI on 23 May 2018 at 11:30 AM
We confront recent experimental results on neutrino mixing parameters with the requirements from strong thermal $SO(10)$-inspired leptogenesis. There is a nice agreement with latest global analyses supporting $\sin\delta < 0$ and normal ordering at $ \sim 95\%$ C.L. On the other hand, the more stringent experimental lower bound on the atmospheric mixing angle starts to corner this paradigm. Prompt ... More
Presented by Dr. Marco CHIANESE on 23 May 2018 at 2:40 PM
The generation of the observed matter-antimatter asymmetry in the universe through baryogenesis cannot be explained in the Standard Model. We therefore investigate the possibility of a strong first order phase transition in the CP-Violating 2-Higgs-Doublet Model (C2HDM) after imposing theoretical and experimental constraints. We study the type I and II C2HDM where one of the neutral Higgs bosons c ... More
Presented by Prof. Margarete MÜHLLEITNER on 23 May 2018 at 2:40 PM
Assuming that new physics effects are parametrized by the Standard-Model Effective Field Theory (SMEFT) written in a complete basis of up to dimension-6 operators, we calculate the CP-conserving one-loop amplitude for the decay h->gamma+gamma in general R_xi-gauges. We use this gauge invariant amplitude and recent LHC data to check upon sensitivity to various Wilson coefficients entering from a m ... More
Presented by Dr. Athanasios DEDES on 22 May 2018 at 4:10 PM
We systematically construct all torically resolved SO(10) theories theories with possible additional (discrete) Abelian gauge symmetries. We show that most of these models are connected via higgsing or superconformal matter transitions involving small E8 instantons. Motivated by this observations, we classify superconformal matter transitions in 6d SUGRA theories with Abelian and non-Abelian gauge ... More
Presented by Dr. Paul-Konstantin OEHLMANN on 23 May 2018 at 2:00 PM
We scrutinize the allowed parameter space of Little Higgs models with the concrete symmetry of T-parity by providing comprehensive LHC analyses of all relevant production channels of heavy vectors, top partners, heavy quarks and heavy leptons and all phenomenologically relevant decay channels. Constraints on the model will be derived from the signatures of jets and missing energy or leptons and mi ... More
Presented by Mr. Daniel DERCKS on 23 May 2018 at 4:10 PM
In this talk I will present a new paradigm for dark matter production in which the dark constituent of our Universe is in contact with the visible bath exclusively through the inflationary sector. I will show that experimental constraints on the inflationary energy scale and the dark matter relic density can be balanced by the use of a very minimal set up and that such a construction allows to con ... More
Presented by Dr. Lucien HEURTIER on 24 May 2018 at 5:10 PM
Horava gravity is a proposal for a non-relativistic UV completion of General Relativity, which has been proven to be renormalizable and (in 2+1 dimensions) asymptotically free while propagating non-trivial degrees of freedom. We review the current status of the theory as a plausible proposal for a description of quantum gravity and describe the main challenges for its success.
Presented by Mario HERRERO VALEA on 24 May 2018 at 2:20 PM
Session: Plenary Session
In this talk we discuss various Theories of Flavour from the Planck scale to the Electroweak Scale, ranging from SUSY GUTs with Flavour Symmetry (with or without extra dimensions) to Flavourful Z' Models at the Electroweak scale capable of accounting for R_K(*).
Presented by Steve KING on 21 May 2018 at 4:30 PM
We construct a model of quark-lepton unification at the TeV scale based on an SU(4) gauge symmetry, while still having acceptable neutrino masses and enough suppression in flavor changing neutral currents. An approximate U(2) flavor symmetry is an artifact of family-dependent gauge charges leading to a natural realization of the CKM mixing matrix. The model predicts sizeable violation of PMNS unit ... More
Presented by Dr. Benjamin STEFANEK on 22 May 2018 at 2:40 PM
The Standard Model Effective Field Theory (SMEFT) provides a consistent formalism to parametrise the effects of heavy new physics appearing as deviations from SM expectations. One of the key goals of the LHC legacy will be to cover this parameter space as much as possible and contribute to a global fit of the EFT parameter space and, hopefully, provide hints on the nature of physics beyond the SM. ... More
Presented by Ken MIMASU on 22 May 2018 at 3:50 PM
We present a comprehensive analysis of top-philic Majorana dark matter that interacts via a colored t-channel mediator. Despite the simplicity of the model - introducing three parameters only - it provides an extremely rich phenomenology allowing to accommodate the relic density for a large range of coupling strengths spanning over six orders of magnitude. This model features all 'exceptional' mec ... More
Presented by Dr. Jan HEISIG on 24 May 2018 at 4:50 PM
Despite great efforts over several decades, neutrinoless double beta decay has not yet been detected and neutrinos could be Dirac particles. In this talk we present a “scotogenic” mechanism relating small neutrino mass and cosmological dark matter. Neutrinos are Dirac fermions with masses arising only in two-loop order through the sector responsible for dark matter. A global spontaneously brok ... More
Presented by Dr. EDUARDO PEINADO on 24 May 2018 at 3:00 PM
Dark matter that is capable of sufficiently heating a local region in a white dwarf will trigger runaway fusion and ignite a type 1a supernova. We consider dark matter (DM) candidates that heat through the production of high-energy standard model (SM) particles, and show that such particles will efficiently thermalize the white dwarf medium and ignite supernovae. Based on the existence of long-liv ... More
Presented by Ryan JANISH on 23 May 2018 at 4:10 PM
The flipped SU(5) unification represents one of the rare cases in which the Witten's loop mechanism for the radiative RH neutrino mass generation may be implemented in a potentially realistic manner. It was shown recently that, in a large part of the parameter space, the tight flavour structure of the minimal model of this kind yields relatively strong constraints on the principal smoking-gun obse ... More
Presented by Michal MALINSKY on 24 May 2018 at 2:20 PM
The classical part of Yukawa couplings from D6-branes is computed by summing over worldsheet instantons. On non-factorisable tori the worldsheet instantons obey selection rules, which depend on the underlying lattice of the torus. Quantum corrections to the couplings are obtained by T-dualizing the setup and computing the overlapping wavefunctions of three chiral matter fields.
Presented by Mr. Christoph LIYANAGE on 23 May 2018 at 2:20 PM