23-26 September 2014

DESY Hamburg

Europe/Berlin timezone

Home > Contribution List

## Contribution List

Displaying 110
contributions
out of
110

Session:
Particle Phenomenology

We show that the decay of the inflaton field may be incomplete, while nevertheless successfully reheating the universe and leaving a stable remnant that accounts for the present dark matter abundance. We note, in particular, that the inflaton field alternately increases and reduces the mass of its decay products as it oscillates about the minimum of its potential. By considering an appropriate dis
... More

Presented by Mr. Rafael CEREZO
on
25 Sep 2014
at
2:40 PM

Session:
Cosmology & Astroparticle Physics A

We revisit the limit on very light axion-like particles from the absence of coincidental gamma rays with the neutrino burst from SN1987A. This is done using updated supernova simulations, updated models for the magnetic field inside the Galaxy, and taking into account the effects of proton degeneracy and mass reduction on the production of these particles in the supernova core.

Presented by Dr. Alexandre PAYEZ
on
24 Sep 2014
at
5:10 PM

Session:
Cosmology & Astroparticle Physics B

With the indications for r > 0.1 by BICEP2, there have been discussions about whether all small-field models of inflation could be ruled out due to the Lyth bound, or if the Lyth bound can be evaded by specific choices of the inflaton potential. We show that in single-field slow-roll inflation, it is impossible to reconcile r > 0.1 with field excursions \Delta \phi << M_pl, independently of the fo
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Presented by David NOLDE
on
24 Sep 2014
at
2:00 PM

Session:
Cosmology & Astroparticle Physics B

Starting from the collisional Boltzmann equation, we derive for the first time and from first principles a Boltzmann hierarchy for neutrinos including neutrino-neutrino interactions mediated by a scalar particle. Such interactions appear, for example, in majoron-like models of neutrino mass generation. In contrast to, e.g., the first-order Boltzmann hierarchy for Thomson-scattering photons, our in
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Presented by Isabel Mira OLDENGOTT
on
25 Sep 2014
at
3:20 PM

Session:
Particle Phenomenology

The LHC allows to probe quantum gravity with large extra dimensions. Within the Asymptotic Safety scenario we present new constraints on the transition scale $\Lambda_T$ for the diphoton channel. These bounds will be compared to existing bounds from other channels, including Drell-Yan and MET plus jet.

Presented by Ms. Magdalena ZENGLEIN
on
24 Sep 2014
at
2:20 PM

Session:
Strings & Mathematical Physics

We discuss the minimal gauge group and matter content for all 16 2D reflexive polytopes, where some of these were already discussed in the literature. The polyhedrons are connected by geometric transitions on the geometry side which translates into a toric Higgs branch on the field theory side. This network structure is symmetric and reflects the mirror symmetry of the polytopes.

Presented by Jonas REUTER
on
24 Sep 2014
at
5:10 PM

Session:
Particle Phenomenology

The difficulties one faces when implementing CP transformations in the presence of finite non-abelian symmetries are reviewed. It is then shown that physical CP transformations in such settings always correspond to class-inverting automorphisms of the finite group and their connection to the existence of bases with real Clebsch-Gordan coefficients is explored. Furthermore, the finite groups are ca
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Presented by Mr. Maximilian FALLBACHER
on
25 Sep 2014
at
4:25 PM

Session:
Particle Phenomenology

Current Ice-Cube analyses show hints for an unexpected neutrino flavor ratio (1:0:0) at high energies. This may point to non-standard
neutrino properties like LSND, MiniBooNE, ractor and Gallium anomalies do, e.g. sterile neutrinos.
Here we discuss the 1+1 active-sterile neutrino mixing resulting from the altered dispersion relations of sterile neutrinos oscillating
around a 3+1 brane in an asy
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Presented by Mr. Philipp SICKING
on
25 Sep 2014
at
4:55 PM

Session:
Cosmology & Astroparticle Physics A

We present a leptogenesis scenario associated with inflationary models involving non-Abelian gauge fields within the standard model of particle physics (SM). We show that this class of inflationary
models generates intrinsic birefringent gravitational waves that through the gravitational chiral anomaly in SM, can naturally create a net lepton number density. The CP violating interaction is produ
... More

Presented by Dr. Azadeh MALEKNEJAD
on
25 Sep 2014
at
4:10 PM

Session:
Cosmology & Astroparticle Physics A

To illustrate the complementarity of the collider and astrophysics bounds on the light (MeV-scale mass) dark matter (DM), the constraints on the dipole DM from the ILC and supernova will be discussed, along with those from the LHC and solar data (helioseismology).

Presented by Dr. kenji KADOTA
on
24 Sep 2014
at
2:00 PM

Session:
Concert: Physics and Music

Rachmaninow: Prélude Op.3 No.2;
Tschaikowski: Dumka Op.59;
Skrjabin: Fantaisie Op.28;
Borodin: Au convent, Nocturne (Petite Suite);
Balarikew: Islamey - Fantaisie orientale;
Mussorgski: Pictures at an Exhibition.

Presented by Kotaro FUKUMA
on
24 Sep 2014
at
7:30 PM

Session:
Particle Phenomenology

The new data from LHC, Planck and BICEP2 provide unseen possibilities for probing the early universe, its particle content and interactions between them. We study the cosmological constraints on a Standard Model extension with a real singlet scalar. I briefly introduce some of the main constraints on formation and decay of the scalar condensates in the early universe in order to consider the gener
... More

Presented by Mr. Tommi TENKANEN
on
25 Sep 2014
at
3:20 PM

Session:
Cosmology & Astroparticle Physics A

In this talk will be presented how different processes may produce distortions in the Fermi-Dirac distribution of cosmological neutrinos and their effects on cosmological observables and parameters. Will be given attention to the standard model and minimum extensions.

Presented by Daniel BORIERO
on
25 Sep 2014
at
2:20 PM

Session:
Cosmology & Astroparticle Physics B

Even though f(R) modifications of late time cosmology is very successful in explaining the cosmic acceleration, it is very difficult to simultaneously satisfy the fifth-force constraint. Even in this case, the effective scalar degree of freedom may move to a point (close to its minima) in the field space where the Ricci scalar diverges. We elucidate this point further with a specific example of f(
... More

Presented by Koushik DUTTA
on
25 Sep 2014
at
5:10 PM

Session:
Cosmology & Astroparticle Physics A

I present extensions of the Standard Model, where the global symmetries baryon and lepton number are gauged and subsequently spontaneously broken. These theories are consistent with collider bounds and cosmology, and have intriguing consequences due to the requirement of anomaly cancellation: lepto-baryon fields that have to be introduced can be a dark matter candidate and/or generate neutrino mas
... More

Presented by Michael DUERR
on
25 Sep 2014
at
3:00 PM

Session:
Strings & Mathematical Physics

The existence of Dark Radiation is a generic prediction of the Large Volume Scenario (LVS), a popular scheme of moduli stabilisation in type IIB string theory. In this talk I will quantify predictions for Dark Radiation for a wide range of LVS models. In particular, I will show that some of the most natural LVS settings with natural values of model parameters lead to Dark Radiation predictions jus
... More

Presented by Dr. Lukas WITKOWSKI
on
25 Sep 2014
at
2:40 PM

Session:
Strings & Mathematical Physics

We propose an uplift mechanism using a structure of multi-K\"ahler moduli dependence in the F-term potential of type IIB string theory compactifications. This mechanism requires a D-term condition that fixes one modulus to be proportional to another modulus, resulting in a trivial D-term potential. De Sitter minima are realized along with an enhancement of the volume in the Large Volume Scenario a
... More

Presented by Dr. Markus RUMMEL
on
25 Sep 2014
at
3:00 PM

Session:
Cosmology & Astroparticle Physics B

Cosmic strings are line-like topological defects associated with symmetry breaking. Though it is often assumed that they are formed after inflation and enters so-called scaling regime at very early Universe, it is possible to let them enter scaling regime at a later time if phase transition takes place during inflation. Here we study its effect on the cosmological observables, in particular cosmi
... More

Presented by Dr. Kohei KAMADA
on
25 Sep 2014
at
4:25 PM

Session:
Cosmology & Astroparticle Physics A

The origin and nature of the ultra-high energy cosmic rays (UHECRs) are still unresolved issues. Ultra-high energy cosmic rays can propagate diffusively in cosmic magnetic fields. When their propagation time is comparable to the age of the universe a suppression of the flux compared to the case without magnetic fields is expected. In this work we parametrize this suppression for different cosmolo
... More

Presented by Rafael ALVES BATISTA
on
24 Sep 2014
at
3:20 PM

Session:
Strings & Mathematical Physics

We study the phenomenological implications of a string-motivated scenario in which supersymmetry breaking is triggered by the Dilaton field. We show that for the MSSM there is a tension between the expected Higgs mass and the dark matter relic abundance. This constrains the parameter space and thus leads to testable predictions for LHC-14. We also present examples within the general singlet extens
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Presented by Mrs. Lucila ZÁRATE
on
24 Sep 2014
at
4:25 PM

Session:
Cosmology & Astroparticle Physics B

We investigate the gauge-invariant cosmological perturbations in the gravity and matter frames in the general scalar-tensor theory where two frames are related by the disformal transformation. The gravity and matter frames are the extensions of the Einstein and Jordan frames in the scalar-tensor theory where two frames are related by the conformal transformation, respectively. First, it is shown t
... More

Presented by Dr. Masato MINAMITSUJI
on
25 Sep 2014
at
4:55 PM

Session:
Cosmology & Astroparticle Physics B

Magnetic fields are ubiquitous in the Universe and their generation mechanism is an open problem in cosmology. Their presence on all scales strengthens the idea of a primordial origin. If this is the case, a magnetic cosmological model has to be built. Here, we discuss the possible effects that primordial magnetic fields can have on a warm inflation scenario, in particular on the inflaton effecti
... More

Presented by Dr. Gabriella PICCINELLI
on
24 Sep 2014
at
4:10 PM

Session:
Cosmology & Astroparticle Physics A

In the framework of Einstein-Maxwell-Vlasov-axion model we
analyzed the dispersion relations for the perturbations in an
initially isotropic and homogeneous axionically active
ultrarelativistic plasma, which expands in the de Sitter-type
cosmological background, and classify the longitudinal and
transversal electromagnetic modes. We show that for the special
choice of the guiding model param
... More

Presented by Dr. Aleksei ZAIATS
on
24 Sep 2014
at
5:25 PM

Session:
Particle Phenomenology

The nature of the electroweak phase transition in two-Higgs-doublet models is revisited
in light of the recent LHC results. A scan over an extensive region of their parameter space is performed, showing that a strongly first-order phase transition favours a light neutral scalar with SM-like properties, together with a heavy pseudo-scalar and a mass hierarchy in the scalar sector. Altogether, the
... More

Presented by Glauber CARVALHO DORSCH
on
25 Sep 2014
at
2:20 PM

Session:
Cosmology & Astroparticle Physics A

Monochromatic gamma ray lines have long been known to provide potential smoking gun signals for annihilating dark matter. Here, we demonstrate that the situation is particularly interesting for Kaluza-Klein dark matter because resonant annihilation is generically expected for small, but not necessarily vanishing relative velocities of the annihilating particles. We calculate the contribution from
... More

Presented by Mr. Martin VOLLMANN
on
24 Sep 2014
at
4:10 PM

Session:
Cosmology & Astroparticle Physics A

Dark matter remains a major gap in the understanding of modern physics with many proposed
routes to direct and indirect detection. In this study we model the radio emission from neutralino annihilation in DM halos assuming various annihilation channels, a model of the magnetic field and an exploration of a range of redshifts. Using this model we provide estimates for the detectability of neutral
... More

Presented by Mr. Geoff BECK
on
24 Sep 2014
at
4:25 PM

Session:
Cosmology & Astroparticle Physics B

We investigate to which extent and under which circumstances false vacuum energy (V0) dominated slow-roll inflation is compatible with a large tensor-to-scalar ratio r=O(0.1), as indicated by the recent BICEP2 measurement. With V0 we refer to a constant contribution to the inflaton potential, present before a phase transition takes place and absent in the true vacuum of the theory, like e.g. in hy
... More

Presented by Dr. Stefano ORANI
on
24 Sep 2014
at
3:00 PM

Session:
Particle Phenomenology

Flavor effects play an important role in the time-evolution of particle number densities in a statistical ensemble with arbitrary flavor content. We present a fully flavor covariant formalism for transport phenomena, which captures consistently all flavor effects. As an application, we study flavor effects in a Minimal Resonant Leptogenesis scenario. In particular, we show that our flavor covarian
... More

Presented by Dr. Bhupal DEV
on
25 Sep 2014
at
3:00 PM

Session:
Cosmology & Astroparticle Physics A

By means of a relativistic microscopic approach we calculate the expansion velocity of bubbles generated during a first-order electroweak phase transition. In particular, we use the gradient expansion of the Kadanoff-Baym equations to set up the fluid system. This turns out to be equivalent to the one found in the semi-classical approach in the non-relativistic limit. Finally, by including hydrody
... More

Presented by Ingo RUES
on
25 Sep 2014
at
4:25 PM

Session:
Cosmology & Astroparticle Physics A

Models which have a dark matter candidate that is a Majorana fermion in most cases contain helicity suppressed annihilation processes. Notable examples of such a scenario are models for supersymmetric neutralino dark matter, in which annihilation into a fermion anti-fermion pair is p-wave suppressed. It is well known that the radiation of a gauge boson can lift helicity suppression, enhancing the
... More

Presented by Dr. Ahmad GALEA
on
24 Sep 2014
at
4:40 PM

Session:
Particle Phenomenology

Lepton flavor violating Higgs decays can arise in flavor symmetry
models where the Higgs sector is responsible for both the electroweak and the flavor symmetry breaking. Here we advocate a minimal $S_4$ Three-Higgs-Doublet-Model with Lepton Flavor Triality. This model can explain the $2.5\,\sigma$ excess of Higgs decay final states with a $\mu\tau $ topology reported recently by CMS if the Standa
... More

Presented by Mr. Erik SCHUMACHER
on
24 Sep 2014
at
2:40 PM

Session:
Cosmology & Astroparticle Physics A

Lorentz invariance is a cornerstone of modern physics. Deviations from exact symmetry would radically change our view of the universe and current experiments allow us to test the validity of this assumption. In this talk, I will describe how the recent observation of high-energy astrophysical neutrinos can be used to constrain violations of Lorentz invariance.

Presented by Dr. Diaz JORGE S.
on
25 Sep 2014
at
3:20 PM

Session:
Strings & Mathematical Physics

We investigate a particular class of scalar field theories with higher-derivative corrections in the context of N=1 supergravity. Special attention is paid to the proper understanding of such theories within the language of effective field theory. Finally the relevance to moduli stabilization as well as inflation is discussed. Specifically the sensitivity of the inflaton potential to the presence
... More

Presented by David CIUPKE
on
24 Sep 2014
at
4:10 PM

Session:
Cosmology & Astroparticle Physics A

I will present a new firsrt principle approach for higher order perturbation theory for massive neutrinos in large scale structure. The approach is based on a non-linear generalization of Gilbert's equation.
Combined with standard perturbation theory, it allows to calculate N-point statistics of density perturbations in mixed cold+hot dark matter cosmologies.
I apply the theory to compute the le
... More

Presented by Mr. Florian FÜHRER
on
25 Sep 2014
at
5:10 PM

Session:
Cosmology & Astroparticle Physics B

Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations caused by Inflation in the early universe. A broad range of single field models of inflation are analyzed in light of all relevant recent cosmological data, checking whether they can lead to the formation of longlived PBHs as candidate for dark matter. To that end we calculate the
... More

Presented by Dr. Encieh ERFANI
on
24 Sep 2014
at
4:25 PM

Session:
Strings & Mathematical Physics

We analyze the feasibility of inflation driven by field-dependent FI terms in the presence of an anomalous U(1) symmetry. We consider a heavy Kähler modulus whose axionic component cancels the gauge anomaly via the Green-Schwarz mechanism, i.e., it shifts under the anomalous U(1). The D-term of the modulus may play the role of a field-dependent FI term which can, in principle, drive inflation. Ho
... More

Presented by Mr. Clemens WIECK
on
25 Sep 2014
at
4:25 PM

Session:
Cosmology & Astroparticle Physics B

A naive perturbation theory predicts that loop corrections generated during inflation suffer from various infrared (IR) divergences. We discuss the origin of the IR divergences and explore the regularity conditions, which will restrict the possible initial states of inflationary universe. This talk is based on our recent works, summarized in the review article, Class.Quant.Grav. 30 (2013) 233001
... More

Presented by Dr. Yuko URAKAWA
on
24 Sep 2014
at
5:10 PM

Session:
Strings & Mathematical Physics

Any N=2 gauge theory in four dimensions contains a set of local
operators made only out of fields in the N=2 vector multiplet that is
closed under renormalization to all loops, namely the SU(2,1|2)
sector. We present a diagrammatic argument that for any planar N=2
theory the SU(2,1|2) Hamiltonian acting on infinite spin chains is
identical to all loops to that of N=4 SYM, up to a redefinition
... More

Presented by Dr. Elli POMONI
on
24 Sep 2014
at
2:40 PM

Session:
Cosmology & Astroparticle Physics B

We show that models of `just enough' inflation, where the slow-roll evolution lasted only 50−60 e-foldings, feature modifications of the CMB power spectrum at large angular scales. We perform a systematic and model-independent analysis of any possible non-slow-roll background evolution prior to the final stage of slow-roll inflation, We find a high degree of degeneracy since all possible backgro
... More

Presented by Francisco PEDRO
on
25 Sep 2014
at
2:20 PM

Session:
Particle Phenomenology

We study the possible signals at LHC of minimal models of decaying dark matter. Those models are characterized by the fact that DM interacts with SM particles through renormalizable coupling with an additional heavier charged state. Such interaction allows to
produce a substantial abundance of DM in the early Universe via the decay of such charged heavy state, either in- or out-of-equilibrium. M
... More

Presented by Mr. Federico DRADI
on
24 Sep 2014
at
2:00 PM

Session:
Particle Phenomenology

We consider lepton flavour observables in the Randall-Sundrum (RS)
model with and without custodial protection.To this end, we apply a fully five dimensional (5D) framework to calculate the matching
coefficients of the effective field theory at the electroweak scale.
This enables us to obtain predictions for the radiative decay $\mu \to e \gamma$ as well as the decay $\mu \to 3\,e $, the anom
... More

Presented by Mr. Paul MOCH
on
25 Sep 2014
at
5:10 PM

Session:
Particle Phenomenology

The search for Supersymmetry at the LHC is an ongoing task. Despite the LHC searches push the limits on coloured sparticles of the first two generations above the 1 − 1.5 TeV range, the lightest stop can still be rather light. The relevant stop search channels in the low-mass region are the flavour-changing neutral current (FCNC) decay of the lightest stop into a charm quark and the lightest neu
... More

Presented by Eva POPENDA
on
24 Sep 2014
at
5:25 PM

Session:
Cosmology & Astroparticle Physics A

In the last recent years different anomalies observed in short-baseline neutrino
oscillation experiments seem to point towards the existence of light sterile neutrinos.
These sterile neutrinos can also be produced in the early universe by oscillations of the
active neutrinos and can affect different cosmological observables. In particular,
their properties can be constrained by their contribut
... More

Presented by Dr. Saviano NINETTA
on
25 Sep 2014
at
2:00 PM

Integrability plays an important role in understanding AdS/CFT. On the string side exact results are typically found through so-called mirror models, which arise by doubly Wick rotating the light cone world sheet theory of a string, as I will briefly review. I will give a direct physical interpretation to such mirror models, coming about naturally when considering a one parameter integrable deform
... More

Presented by Dr. Stijn VAN TONGEREN

Session:
Strings & Mathematical Physics

We present preliminary results regarding the validity of inflation being driven by Kahler moduli fields in Calabi-Yau compactifications of arbitrary dimension. By studying the moduli space geometry in the supergravity limit of F-theory constructions, we are able to test the viability of modular inflation in the context of Type IIA/B and M-theory. We end by commenting on a mathematical inconsistenc
... More

Presented by Mr. Richard GALVEZ
on
25 Sep 2014
at
3:20 PM

Session:
Particle Phenomenology

The search for supersymmetry is a central task of the Large Hadron Collider. The interpretation of the experimental data requires accurate and flexible theoretical predictions. We present a new calculation of the next-to-leading order supersymmetric-QCD corrections to the production and the decay of squarks. In particular, we provide fully differential cross sections matched to parton showers. We
... More

Presented by Mathieu PELLEN
on
24 Sep 2014
at
4:55 PM

Session:
Particle Phenomenology

The search for supersymmetry is an ongoing quest during the future runs of the LHC. Coloured supersymmetric particles are expected to be produced in large quantities due to the high production cross sections, should supersymmetry be realised in nature. Precise theoretical predictions are therefore needed to improve the search for these yet undiscovered particles. A way to increase precision, and t
... More

Presented by Mr. Christoph BORSCHENSKY
on
24 Sep 2014
at
4:25 PM

Session:
Strings & Mathematical Physics

A novel framework is proposed for embedding the natural inflation into the type IIA superstrings compactified on a Calabi-Yau three-fold. Inflaton is identified with axion of the universal hypermultiplet (UH). The other UH scalars (including dilaton) are stabilized by the CY fluxes whose impact can be described by gauging of the abelian isometry associated with the axion, when the NS5-brane instan
... More

Presented by Prof. Sergei KETOV
on
25 Sep 2014
at
4:55 PM

Session:
Cosmology & Astroparticle Physics A

I will concentrate on the link between leptogenesis and low-energy neutrino data, showing how the baryon asymmetry of the Universe can constrain a type- I seesaw model and yield interesting predictions on the neutrino parameters. To this aim, I will consider the conditions required by strong thermal leptogenesis, where the final asymmetry is fully independent of the initial conditions. In this fra
... More

Presented by Michele RE FIORENTIN
on
25 Sep 2014
at
4:40 PM

A new technique is presented in order to build tetrads in a 4-dimensional Einstein-Maxwell spacetime. These tetrads have special useful properties in relativity and also particle physics. A new fundamental result is proved in group theory. The group SO(2) (spatial rotations) is isomorphic to the group SO(1,1) (boosts) plus two kinds of discrete transformations. That is, a compact group is isomorph
... More

Presented by Dr. Alcides GARAT

Session:
Cosmology & Astroparticle Physics B

If cosmic magnetic fields are produced during inflation, they are likely to be correlated with the primordial curvature perturbations that are responsible for the Cosmic Microwave Background anisotropies and Large Scale Structure. We compute the three-point cross-correlation function of the curvature perturbation with two powers of the electromagnetic field in a typical model of inflationary magne
... More

Presented by Dr. Rajeev Kumar JAIN
on
25 Sep 2014
at
4:10 PM

Session:
Particle Phenomenology

Deep-inelastic $ep$ scattering receives essential contributions from heavy
flavors. The determination of the strong coupling constant $\alpha_s$ and the
charm quark mass $m_c$ are sensitive to NNLO corrections. In the asymptotic
region where the momentum transfer $Q^2$ is large compared to the mass of the
heavy quark $m^2$ the heavy flavor contributions factorize into massless
Wilson coeffici
... More

Presented by Arnd BEHRING
on
24 Sep 2014
at
4:10 PM

Session:
Strings & Mathematical Physics

Non-linear sigma-models play an important role in physics and mathematics. In String Theory they are extensively used to describe compactifications. Homogeneous target spaces are particularly relevant. In the context of the AdS/CFT correspondence, sigma-models based on supergroups play an important role.
Understanding sigma-models at small radius of the target space is of central importance. To t
... More

Presented by Mr. Václav TLAPÁK
on
24 Sep 2014
at
4:55 PM

Session:
Cosmology & Astroparticle Physics B

The detection of the imprints of the primordial tensor perturbations by BICEP2 and its indication of a rather high tensor-to-scalar ratio, if confirmed, can open up a new window for understanding the tensor perturbations, not only at the level of the power spectrum, but also in the realm of non-Gaussianities. In this work, we consider the consistency relations associated with the three-point cross
... More

Presented by Mr. Sreenath VIJAYAKUMAR
on
24 Sep 2014
at
5:25 PM

Session:
Particle Phenomenology

Many new physics models contain new particles that interact with the Higgs boson. These particles could be produced at the LHC via gluon-gluon fusion with an off-shell Higgs, as well as via the Drell-Yan process if charged under a gauge group. We consider simplified scenarios where the Standard Model is extended by one scalar or fermionic field that interacts with the Higgs boson and we evaluate t
... More

Presented by Mr. Andre HESSLER
on
24 Sep 2014
at
4:40 PM

Session:
Strings & Mathematical Physics

It is well known that the scalar degrees of freedom of a generic $f(R)$ theory could be recast in a field theory dual using a Weyl scaling of the metric. In this work, we explore how the RG-improved Higgs Inflation model could be seen as a corrected Starobinsky model, showing that the relation between this two models correspond not only to a tree level matching, but at least to a 1-loop level. We
... More

Presented by Mr. Mario GALANTE
on
25 Sep 2014
at
4:10 PM

Session:
Strings & Mathematical Physics

We study partial supersymmetry breaking of five-dimensional N=4 gauged supergravity in consistent truncations ofsupergravity and string theory. Evaluating one-loop Chern-Simons terms we address necessary conditions for consistent truncations to yield also proper effective field theories. As examples we consider SU(2)-structure reduction of M-theory on Calabi-Yau threefolds with vanishing Euler num
... More

Presented by Mr. Andreas KAPFER
on
24 Sep 2014
at
2:20 PM

Session:
Cosmology & Astroparticle Physics A

I describe a scenario in which the 3.55 keV photon line recently observed in galaxy clusters and Andromeda is caused by dark matter decay to axion like particles (ALPS), which then mix with the photon in astrophysical magnetic fields. This model is particularly well motivated by the observed morphology of the 3.55 keV flux. In particular, I describe predictions for Milky Way halo dark matter decay
... More

Presented by Ms. Francesca DAY
on
24 Sep 2014
at
3:00 PM

Session:
Cosmology & Astroparticle Physics B

We constrain several models of the early Universe that predict statistical anisotropy of the cosmic microwave background (CMB) sky. We make use of WMAP9 and Planck maps deconvolved with beam asymmetries. As compared to previous releases of CMB data, they do not exhibit the anomalously large quadrupole of statistical anisotropy. This allows to strengthen the limits on the parameters of models estab
... More

Presented by Dr. Sabir RAMAZANOV
on
25 Sep 2014
at
2:40 PM

Session:
Cosmology & Astroparticle Physics B

We investigate the variant of the Affleck-Dine mechanism in high-scale inflation. The scenario utilizes multiple flat directions, which is generally present in the MSSM. One flat direction creates baryon asymmetry of the universe, while Q balls from another direction can be the dark matter in the gauge-mediated supersymmetry breaking. Isocurvature fluctuations are suppressed by the fact that the A
... More

Presented by Dr. Shinta KASUYA
on
24 Sep 2014
at
4:40 PM

Session:
Strings & Mathematical Physics

Inspired by asymptotically free quantum gravity, we consider a nonlocal scalar field theory toy model that is ghost-free. We consider one-loop and two-loop Feynman diagrams and assess the divergence structure of those diagrams. We discuss the renormalizability of the theory, in contrast with General Relativity (GR). Finally, we indicate how our work will contribute to the establishment of a unitar
... More

Presented by Mr. Spyridon TALAGANIS
on
24 Sep 2014
at
4:40 PM

Session:
Particle Phenomenology

Flavor changing neutral current |\Delta B|=|\Delta S|=1 processes are sensitive to possible new physics at the electroweak scale and beyond, providing detailed information about flavor, chirality and Lorentz structure. Recently the LHCb collaboration announced a 2.6 \sigma deviation in the measurement of R_K={\cal{B}}(\bar B \to \bar K \mu \mu)/{\cal{B}}(\bar B \to \bar K ee) from the standard mod
... More

Presented by Prof. Gudrun HILLER
on
25 Sep 2014
at
4:40 PM

Session:
Cosmology & Astroparticle Physics A

There is an increasing interest in accurate dark matter relic density
predictions, which requires next-to-leading order (NLO) calculations.
The method applied up to now uses zero-temperature NLO calculations
of annihilation cross sections in the standard Boltzmann equation
for freeze-out, and is conceptually problematic, since it ignores the
finite-temperature infrared (IR) divergences f
... More

Presented by Mr. Francesco DIGHERA
on
24 Sep 2014
at
2:40 PM

Session:
Cosmology & Astroparticle Physics A

In the minimal supersymmetric standard model (MSSM) the lightest superpartner of the left-handed neutrinos is ruled out of being a candidate of dark matter because of its large elastic cross-section with the nucleus mediated via Z-boson. We resurrect it by extending the MSSM with two triplets with opposite hypercharge. The addition
of the triplets not only play a role in generating small Majoran
... More

Presented by Dr. Narendra SAHU
on
25 Sep 2014
at
4:55 PM

Session:
Cosmology & Astroparticle Physics A

A very exciting challenge in particle and astroparticle physics is the exploration of the nature of dark matter. The striking evidences of the existence of dark matter
are also the strongest phenomenological indications for physics beyond the Standard Model.
A huge experimental effort is currently made at colliders and via astrophysical experiments to shed light on the nature of dark matter.
Mo
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Presented by Leila ALI CAVASONZA
on
24 Sep 2014
at
2:20 PM

Session:
Particle Phenomenology

We study the phenomenology of the Standard Model (SM) Higgs sector extended by two singlet scalars. The model has two CP-even scalars h_{1,2} where one of them corresponds to the observed 125 GeV scalar
resonance; in addition to a scalar singlet that can be stable and plays the role of a dark matter candidate. We discuss the effect of the extra scalars on the Higgs triple couplings and show that
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Presented by Dr. Amine AHRICHE
on
24 Sep 2014
at
3:00 PM

Session:
Strings & Mathematical Physics

We present soft supersymmetry breaking terms in type IIB de Sitter string vacua
after moduli stabilisation. We focus on models in which the Standard Model is sequestered from the supersymmetry breaking sources and the spectrum of soft-terms is hierarchically smaller than the gravitino mass.

Presented by Dr. Sven KRIPPENDORF
on
24 Sep 2014
at
2:00 PM

Session:
Strings & Mathematical Physics

We propose a framework for inflationary model building in supergravity which requires only one chiral superfiled in addition to the standard gravity supermultiplet. A stabilization mechanism for the non-inflaton field in the inflaton supermultiplet is required, for which we take a higher dimensional term in the Kahler potential. This framework allows one to construct a very wide range of inflati
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Presented by Mr. Takahiro TERADA
on
25 Sep 2014
at
4:40 PM

Session:
Cosmology & Astroparticle Physics B

The measurement of primordial tensor modes in the CMB allows for a determination of the energy scale at the beginning of the `observable' part of inflation. We show in how far such a measurement provides implications for the subsequent phase of inflation and the post-inflationary phase of reheating. Further, we will revise the gravitino problem and show the implications for a supersymmetric scenar
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Presented by Dr. Jan HEISIG
on
24 Sep 2014
at
2:40 PM

Session:
Particle Phenomenology

It is currently widely accepted that for a high scale of inflation the EW Higgs vacuum is unstable during inflation due to large fluctuations of order H. However, this conclusion is reached by neglecting potentially significant effects induced by the spacetime curvature. In this talk I review the derivation of a one-loop SM Higgs effective potential in curved space and discuss its implications. In
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Presented by Tommi MARKKANEN
on
25 Sep 2014
at
2:00 PM

Session:
Strings & Mathematical Physics

The QCD axion solving the strong CP problem may originate from antisymmetric tensor gauge fields in compactified string theory, with a decay constant around the GUT scale. Such possibility is in tension with high scale inflation because too large isocurvature perturbations would be generated. A more interesting and still viable possibility is that the string theoretic QCD axion is charged under an
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Presented by Dr. Kwang Sik JEONG
on
25 Sep 2014
at
2:20 PM

Session:
Strings & Mathematical Physics

Double field theory is a proposal to incorporate T-duality as a symmetry of a field theory defined on a formally doubled configuration space. Its gauge transformations are governed by the so-called C-bracket which reduces to the Courant bracket of Hitchin and Gualtieri's generalized geometry by solving the "strong constraint", i.e. projecting to a physical configuration space.
By giving an inter
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Presented by Dr. Andreas DESER
on
24 Sep 2014
at
3:00 PM

Session:
Particle Phenomenology

We discuss effective operators describing interactions between dark matter and Standard Model particles. We are particularly interested in higher-dimensional operators, since they are typically suppressed compared to the leading order effective operators. This can explain why no conclusive direct dark matter detection has been made so far. The ultraviolet completions of the effective operators, wh
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Presented by Dr. Martin KRAUSS
on
24 Sep 2014
at
3:20 PM

Session:
Cosmology & Astroparticle Physics B

In this talk, I discuss how a period of `chaotic inflation' with a sizeable tensor-to-scalar ratio naturally arises from the decay of a false vacuum of GUT-scale energy. We consider D-term inflation for small couplings of the inflaton to matter fields. Standard hybrid inflation then ends at a critical value of the inflaton field that exceeds the Planck mass. During the subsequent waterfall transit
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Presented by Valerie DOMCKE
on
24 Sep 2014
at
3:20 PM

Session:
Cosmology & Astroparticle Physics A

Observations have revealed diffuse excess emission in a large number of galaxy clusters in the ~200 eV soft X-ray band: the Cluster Soft X-ray Excess. In this talk I will discuss how a primordially generated background of relativistic axion-like particles can explain this puzzling feature of galaxy cluster observations. Such a background is generically predicted to be produced from the decays of s
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Presented by Mr. Andrew J. POWELL
on
24 Sep 2014
at
4:55 PM

Session:
Cosmology & Astroparticle Physics B

The AMS-02 experiment is measuring the cosmic ray antiproton flux with high precision. The interpretation of the upcoming data requires a thorough understanding of the secondary antiproton background. Newly available data of the NA49 experiment at CERN will be discussed in order to recalculate the antiproton source term arising from cosmic ray spallations on the interstellar matter. A detailed com
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Presented by Rolf KAPPL
on
25 Sep 2014
at
4:40 PM

Session:
Cosmology & Astroparticle Physics B

We investigate the nature of inflationary parameters at large values of the number of e-foldings N. We analyze the behaviour of the inflationary field range in such a limit and provide strong evidence for universality features of it. Finally, we use these results in order to derive a model-independent field range bound as a function even of the spectral index. We show that Planck's measurement of
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Presented by Mr. Marco SCALISI
on
24 Sep 2014
at
2:20 PM

Session:
Cosmology & Astroparticle Physics B

Inflationary attractors predict the spectral index and tensor-to-scalar ratio to take specific values that are consistent with Planck. Moreover, in this letter we demonstrate that they also give rise to a specific relation between the amplitude of the power spectrum and the number of e-folds. We investigate this relation in the context of the universal attractor for models with a generalised
non-
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Presented by Mr. Benedict BROY
on
25 Sep 2014
at
2:00 PM

Session:
Cosmology & Astroparticle Physics B

We discuss how the time-flow approach of cosmological perturbation theory can be used as a tool for large-scale structure. In particular, we show that the flow equations allow to derive straightforwardly consistency relations for equal-time correlators involving both density and velocity fields and underlying different background cosmologies. Furthermore, we use the time-flow approach to proof the
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Presented by Laura SAGUNSKI
on
25 Sep 2014
at
3:00 PM

Session:
Particle Phenomenology

We determine the mass of the bottom quark from moments of the $b\bar{b}$ production cross section near threshold. On the theory side we use NNNLO predictions both for the resonances and the continuum cross section. We compare our result to other recent precision determinations.

Presented by Mr. Thomas RAUH
on
24 Sep 2014
at
5:10 PM

Session:
Cosmology & Astroparticle Physics B

Thermal inflation is a compelling solution to the cosmological moduli problem. In the cosmological scenario with thermal inflation, while the perturbations on large scales are preserved but slightly red shifted, the perturbations on small scales would be altered. The largest characteristic scale of thermal inflation is found at the comving scale of the horizon size when thermal inflation changes t
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Presented by Dr. Heeseung ZOE
on
24 Sep 2014
at
4:55 PM

Session:
Cosmology & Astroparticle Physics A

Despite the astonishing success of standard ΛCDM cosmology, there is mounting evidence for a tension with observations at small and intermediate scales. We introduce a simple model where both, cold dark matter (DM) and sterile neutrinos, are charged under a new U(1)_X gauge interaction. The resulting DM self-interactions resolve the tension with the observed abundances and internal density struct
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Presented by Jasper HASENKAMP
on
25 Sep 2014
at
2:40 PM

Session:
Particle Phenomenology

We study gravity with torsion in extra dimensions and derive an effective four-dimensional theory containing four-fermion contact operators at the fundamental scale of quantum gravity in the TeV range. These operators may have an impact on the low-energy observables and can manifest themselves or can be constrained in precision measurements. We calculate possible contributions of these operators t
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Presented by Cristóbal CORRAL
on
25 Sep 2014
at
4:10 PM

Session:
Strings & Mathematical Physics

We compute the null cusp anomalous dimension of ABJM theory at strong coupling up to two-loop order. This is done by evaluating corrections to the corresponding superstring partition function, weighted by the AdS4×CP3 action in AdS light-cone gauge. We compare our result, where we use an anomalous shift in the AdS4 radius, with the cusp anomaly of N=4 SYM, and extract the two-loop contribution to
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Presented by Mr. Edoardo VESCOVI
on
25 Sep 2014
at
2:00 PM

Session:
Strings & Mathematical Physics

Unitarity techniques have proven to be a powerful tool for the computation of scattering amplitudes in three and four dimensions. Here the same method is applied to several massive two-dimensional models, including new results for the world-sheet AdS3×S3xM4 superstring, to compute 2→2 scattering S-matrices at one loop from tree level amplitudes. Evidence is found for a hidden relation with the
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Presented by Mr. Lorenzo BIANCHI
on
24 Sep 2014
at
3:20 PM