Conveners
T06: QCD and Hadronic Physics: Part 1: Exclusive physics and diffraction
- Ferenc Siklér (Wigner RCP, Budapest)
- Mateusz Dyndal (AGH UST Krakow)
T06: QCD and Hadronic Physics: Part 2: Jets
- Mateusz Dyndal (AGH UST Krakow)
T06: QCD and Hadronic Physics: Part 3: PDFs
- laura Fabbietti (TUM)
T06: QCD and Hadronic Physics: Part 4: Quarkonia and heavy flavour
- Daniel Johnson (CERN)
T06: QCD and Hadronic Physics: Part 5: V + jets
- Mateusz Dyndal (AGH UST Krakow)
T06: QCD and Hadronic Physics: Part 6: Soft physics
- laura Fabbietti (TUM)
- Ferenc Siklér (Wigner RCP, Budapest)
T06: QCD and Hadronic Physics: Part 7: Exotica
- Daniel Johnson (CERN)
T06: QCD and Hadronic Physics: Part 8: Low-energy phenomena
- Ferenc Siklér (Wigner RCP, Budapest)
T06: QCD and Hadronic Physics: Part 9: Precision calculations
- Zoltan Nagy (T (Phenomenology))
Description
Note: All contributions are given 12 minutes + 3 min for questions
Exclusive photoproduction of $\rho^0(770)$ mesons is studied using the H1 detector at the $ep$ collider HERA. A sample of about 900000 events is used to measure single- and double-differential cross sections for the reaction $\gamma{}p\to \pi^{+}\pi^{-}Y$. Reactions where the proton stays intact ($m_Y=m_p$) are statistically separated from those where the proton dissociates to a low-mass...
Abstract attached as pdf file.
We discuss mechanisms of dilepton production in proton-proton collisions with rapidity gap in the main detector and one forward proton in the forward proton detectors. This is relevant for LHC measurements by ATLAS+AFP and CMS+PPS. Transverse momenta of the intermediate photons are included and photon fluxes are expressed in terms of proton electromagnetic form factors and structure...
In this talk we present various measurements of diffractive physics and soft QCD processes performed using data collected by the ATLAS experiment at the LHC. Single diffractive processes (pp->pX) are studied reconstructing the particles from the dissociative system (X) with the ATLAS detector, while the intact proton is reconstructed and measured in a forward detector. If available, this talk...
In this talk we present our theoretical results for the single-diffractive production of open heavy flavor mesons and non-prompt charmonia in pp and pA collisions. Using the color dipole framework, we found that this mechanism constitutes 0.5-2 per cent of the inclusive production of the same mesons. In Tevatron kinematics our theoretical results are in reasonable agreement with the available...
We discuss the possibility to use the exclusive $pp \to pp \phi$ and $pp \to pp \phi \phi$ reactions in identifying the odderon exchange, the charge conjugation C = -1 counterpart of the C = +1 pomeron. The odderon was introduced on theoretical grounds in [1]. Results of the TOTEM collaboration suggest that the odderon exchange can be responsible for a disagreement of theoretical calculations...
We describe an analysis comparing the $p\bar{p}$ elastic cross section as measured by the D0 Collaboration at a center-of-mass energy of 1.96~TeV to that in $pp$ collisions as measured by the TOTEM Collaboration at 2.76, 7, 8, and 13 TeV using a model-independent approach. The TOTEM cross sections, extrapolated to a center-of-mass energy of $\sqrt{s} =$ 1.96 TeV, are compared with the D0...
Measurements of jet production are sensitive to the strong coupling constant, high order perturbative calculations and parton distribution functions. In this talk we present the most recent ATLAS measurements in this area at a centre-of-mass energy of sqrt(s) = 13 TeV. We present measurements of variables probing the properties of the multijet energy flow and of the Lund Plane using charged...
Measurement of inclusive jet cross sections in proton collisions at 5 and 13 TeV with the CMS experiment are presented. Measurements are performed as a function of the jet transverse momentum pT and jet rapidity. Jets are reconstructed using the anti-kT clustering algorithm with different size parameters in a wide phase space region in jet pT and jet rapidity. The measured jet cross sections...
We present predictions of the distribution of groomed heavy jet mass in electron-positron collisions at the next-to-next-to-leading order accuracy matched with the resummation of large logarithms to next-to-next-to-next-to-leading logarithmic accuracy. Resummation at this accuracy is possible through extraction of necessary two-loop constants and three-loop anomalous dimensions from...
Precision measurements of jet substructure are used as a probe of fundamental QCD processes. The primary Lund jet plane density is a two-dimensional visual representation of the radiation off the primary emitter within the jet that can be used to isolate different regions of the QCD phase space.
A new measurement of the primary Lund plane density for inclusive charged-particle jets in the...
Various measurements related to the study of hadronic jets substructure in proton collisions at 13 TeV with the CMS experiment are presented. The differential jet production cross section as a function of the jet mass and transverse momentum is shown in events with a Z boson plus jet topology, with and without the soft radiation within a jet removed by a jet grooming algorithm. Measurement of...
Jets can be used to test our understanding of quantum chromodynamics (QCD). Specifically, jet-substructure observables measured in proton-proton (pp) collisions constrain perturbative (p)QCD calculations, as well as non-perturbative physics effects such as hadronization, and serve as a baseline to compare to measurements in heavy-ion collisions, where a deconfined state of matter is expected...
A first measurement of the 1-jettiness event shape observable in neutral-current deep-inelastic electron-proton scattering is presented. The 1-jettiness observable $\tau^1_b$ is defined such that it is equivalent to the thrust observable in the Breit frame, following momentum conservation. The data were taken with the H1 detector at the HERA $ep$ collider at a center-of-mass energy of 319 GeV...
After the triumph of discovering the Higgs boson at the CERN Large Hadron Collider, people are getting increasingly interested in studying the Higgs properties in detail and searching for the physics beyond the Standard Model (SM). A multi-TeV lepton collider provides a clean experimental environment for both the Higgs precision measurements and the discovery of new particles. In high-energy...
Recent developments of the xFitter PDF analysis package and studies based on it are summarised. The emphasis is given to the PDF analysis of the Z boson polarisation data which provide additional constraint to the gluon distribution for Bjorken x below 0.1. Studies using pseudo data samples corresponding to an integrated luminosity of the LHC Run 3 and high-luminosity HL-LHC show that the PDF...
Building upon the most recent CT18 global fit, we present:
1) A new calculation of the photon content of proton based on an application of the LUXqed formalism.
2) The impact of heavy-flavor production data on the CT18 PDFs family.
CT18 Photon PDF: We explore two principal variations of the LUXqed ansatz. In one approach which we designate CT18lux, the photon PDF is calculated directly...
We present a new release of the NNPDF family of global analyses of the proton's parton distribution functions: NNPDF4.0. It includes a wealth of new experimental data from HERA and the LHC, from dijet cross-sections and isolated photons to single-top and top-quark pair differential distributions. The NNPDF4.0 methodology benefits from improved machine learning algorithms, in particular...
We present fits to determine parton distribution functions (PDFs) using inclusive W/Z-boson measurements from the ATLAS experiment at the LHC. The ATLAS measurements are used in combination with deep-inelastic scattering data from HERA. We also present the results of PDF fits that use W/Z+jets measurements from ATLAS in addition to the measurements listed above. An improved determination of...
The LHeC and the FCC-he are the cleanest, high resolution microscopes that the world can build in the nearer future. Through a combination of neutral and charged currents and heavy quark tagging, they will unfold the parton structure of the proton with full flavour decomposition and unprecedented precision. In this talk we will present the most recent studies on the
determination of proton...
The Parton Branching (PB) approach provides a way to obtain transverse momentum dependent (TMD) parton densities. Its equations are written in terms of splitting functions and Sudakov form factors and can be solved with Monte Carlo methods. Even though the transverse momentum is known in every branching, the PB method currently uses the DGLAP splitting functions, which assume that the parton...
Recently, jet measurements in DIS events close to Born kinematics have been proposed as a new probe to study transverse-momentum-dependent (TMD) PDFs, TMD fragmentation functions, and TMD evolution. We report measurements of lepton-jet momentum imbalance and hadron-in-jet correlations in high-$Q^2$ DIS events collected with the H1 detector at HERA. The jets are reconstructed with the kT...
In this talk we present exploratory studies of the 3D gluon content of the proton, as a result of analyses on leading-twist transverse-momentum-dependent (TMD) gluon distribution functions, calculated in a spectator model for the parent proton. Our formalism embodies a fit-based parameterization for the spectator-mass density, suited to describe both the small and the moderate-x regime....
The production of quarkonia, bound states of heavy quark-antiquark pairs, in hadronic collisions is a unique testing ground for our understanding of QCD as the theory of the strong interaction. The hard scattering that produces the heavy-quark pair can be described within perturbative QCD, whereas the evolution of this pair into a colorless bound state involves soft scales. At LHC energies,...
Recent CMS results on spectroscopy of heavy mesons and baryons are reported.
In this contribution, we present the latest measurements of $\Lambda^{+}_{\rm c}$, $\Xi^{+,0}_{\rm c}$, $\Sigma^{0,++}_{\rm c}$, and the first measurement of $\Omega^{0}_{\rm c}$ baryons performed with the ALICE detector at midrapidity in pp collisions at $\sqrt{s}$ = 5.02 and 13 TeV. Recent measurements of charm-baryon production at midrapidity by the ALICE Collaboration in small systems show...
Although the charmonium spectrum seems to be well investigated, charmonia can still be used as benchmarks to test our QCD predictions, as these states lay in the transition region between perturbative and non-perturbative QCD.Despite the need for experimental confirmations, setbacks arise from limited statistics because of the production processes of all non-vector states. The
properties and...
Precision hadron spectroscopy helps in understanding how the matter is made around us. The large data sample accumulated by the Belle experiment at the KEKB asymmetric-energy $e^{+}e^{-}$ collider provides us a unique opportunity to perform these studies. We report recent results on charmed baryon spectroscopy from Belle, which include a study on the spin and parity of $\Xi_{c}(2970)$ and...
A precise measurement of the Lambda_b production asymmetry is critical to the measurements of CP violation in the decay of b-baryons at LHCb. In general these production asymmetries cannot be precisely predicted since they require knowledge of non perturbative b-quark hadronisation processes, and so need to be experimentally determined. The semileptonic Lambda_b->Lambda_c mu nu decay offers an...
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is an upgrade of the B factory facility at KEK in Tsukuba, Japan. The experiment began operation in 2019 and aims to record a factor of 50 times more data than its predecessor. Belle II is uniquely capable of studying the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First...
LHCb is a spectrometer that covers the forward region of proton-proton collisions, corresponding to the pseudo-rapidity range 2<eta<5. In this unique phase space, LHCb can perform tests of perturbative and non-perturbative QCD models, by studying the production of heavy flavor quarks, like charm and top quarks. In this context the production of a Z boson in association with a c-jet can be...
Calculations of Drell-Yan production at next-to-leading (NLO) order have been combined with transverse Momentum Dependent (TMD) distributions obtained with the Parton Branching (PB). For the first time, the predictions show a remarkable agreement with DY measurements across a wide range of DY mass and center of mass energies, from experiments like NuSea, R209, Phenix, CMS and ATLAS....
The study of the associated production of vector bosons and jets constitutes an excellent enviroment to check numerous QCD predictions. Total and differential cross sections of vector bosons produced in association with jets have been studied in pp collisions using CMS data. Differential distributions as function of a broad range of kinematical observables are measured and compared with...
The production of prompt isolated photons and W/Z-boson
in association with jets are an important test of perturbative QCD prediction and also yield information about the parton distribution functions of the proton.
In this talk, we present the latest measurements of prompt photon production using proton-proton collision data collected by the ATLAS experiment at √s=13 TeV. This includes...
Heavy-flavored emissions have been always considered as an excellent channel to test properties of Quantum chromodynamics (QCD) at present and future colliders. Among different regimes, in which heavy-flavor production can be investigated, we focus our attention on the semi-hard one, where $s>>Q^2>>\Lambda_{QCD}$ (s is the squared center-of-mass energy, $\{Q^2\}$ a (set of) hard scale(s)...
Charged particle multiplicity distributions in positron-proton deep inelastic scattering at a centre-of-mass energy $\sqrt{s}=319$ GeV are measured. The data are collected with the H1 detector at HERA corresponding to an integrated luminosity of $136$ pb$^{-1}$. Charged particle multiplicities are measured as a function of photon virtuality $Q^2$, inelasticity $y$ and pseudorapidity $\eta$ in...
The large data sample of high-multiplicity pp collisions collected by ALICE allows for the precise measurement of the size of the source producing primary hadrons, opening the door to the study of the interaction of different hadron species using femtoscopy techniques. The momentum correlation between (anti)protons and (anti)deuterons measured in pp collisions at $\sqrt{s}=$ 13 TeV with ALICE...
The energy densities reached in high-energy hadronic collisions at the LHC allow significant production of light (anti)nuclei. Their production yields have been measured as a function of $p_{\mathrm{T}}$ and charged-particle multiplicity in different collision systems and at different center-of-mass energies by ALICE. One of the most interesting results obtained from such a large variety of...
The study of the production of particles of different masses as a function of event multiplicity is a key tool for understanding the soft QCD processes and hadronization. In this talk, we report ALICE results on transverse momentum spectra and yields of $\pi$, K, p, $K^{0}_{S}$, $\Lambda$, $\Xi$ and $\Omega$ measured in pp, p-A, and A-A collisions, including the recently published results in...
The very forward energy detected by the ALICE Zero Degree Calorimeters (ZDC) measures the beam remnants, whose energy decreases as the activity at midrapidity increases. A pseudorapidity gap of nearly 9 units between the ZDC ensures that any correlation between the very forward energy and the midrapidity production originates in the initial scatterings. The measurement of...
With a unique geometry covering the forward rapidity region, the LHCb detector provides unprecedented kinematic coverage at low x for charged particles in hadron collisions. The excellent momentum resolution, vertex reconstruction, and particle identification allows precision measurements down to very low pT. This talk will present recent LHCb measurements of prompt charged hadron production...
Originally conceived for precise luminosity measurements, the gas injection system SMOG currently allows the unique LHCb detector capabilities to be exploited for fixed-target studies in proton-gas collisions at sqrt(s) ~ 100 GeV. The first results obtained with SMOG data are reported: antiproton production with a He target and J/psi , D0 productions in pHe and pAr collisions. The upgraded...
Recently studies of the heavy J/ψ and D-mesons by ALICE and STAR collaborations revealed a pronounced dependence of the cross-section on multiplicity of co-produced charged particles, and one of the possible explanations of this phenomenon is the enhanced contribution of multipomeron configurations. In this talk we present our theoretical results for the production of P-wave quarkonia (χ_c...
Many mesons with additional valence constituents with respect to the conventional quark-antiquark pair have been discovered in the last decades, leading to a renaissance of hadron spectroscopy. Interpretations of such states span from compact objects to hadronic molecules and searches for new exotic meson candidates provide important insights on the quarks binding mechanisms inside hadrons. In...
Due to the high production of light mesons J/ψ radiative and hadronic decays, the largest sample of J/ψ events accumulated at the BESIII detector offers a unique laboratory to study the light mesons spectroscopy and search for the light exotic states. In this talk, we shall report the recent progresses on the light meson spectroscopy achieved at BESIII.
We discuss the production mechanism of a new state, a fully charm tetraquark, discovered recently by the LHCb at M = 6.9 GeV in the $J/\psi J/\psi$ channel. Both single parton scattering (SPS) and double parton scattering (DPS) mechanisms are considered. We calculate the distribution in the invariant mass of the four-quark system $M_{4c}$ for SPS and DPS production of $c c \bar c \bar c$ in...
The LHCb experiment reported the first observation of pentaquark candidates in 2015, opening a new era in hadron spectroscopy. Since then, other pentaquark candidates, either with hidden-charm or charm-strange quarks content, have been reported by the LHCb collaboration. This talk presents the recent results on pentaquark spectroscopy at LHCb.
In e+e- collisions between 2 and 3 GeV, excited states of rho, omega and phi can be produced directly. Especially the resonances around 2GeV like rho(2000), rho(2150) and \phi(2170) are not fully understood yet. Theorists describe the phi(2170) as a traditional s s-bar state, an s s-bar g hybrid, a tetraquark state, a Lambda Lambda-bar bound state, or a phi KK resonance. The predicted decay...
The Belle II experiment has accumulated data corresponding to 89.99 fb-1 integrated luminosity in the past 2 years, and is performing very good. Waiting that the full planned data set will be recorded (50 ab-1), which will allow search for rare processes and will have a tremendous impact in the spectroscopy field, the Phase 3 data set allows to already perform analysis with high precision. We...
Recent result on $e^+e^−$ annihilation to hadrons below 2 GeV obtained at the SND experiment at the VEPP-2000 collider are presented. In particular, we discuss measurements of the $e^+e^-\to\pi^+\pi^-$ and $e^+e^-\to n\bar{n}$ cross sections, and study of the radiative processes $e^+e^-\to \eta\gamma$, $e^+e^-\to \eta\pi^0\gamma$, and $e^+e^-\to \eta\eta\gamma$.
In this talk recent XYZ results at BESIII will be reviewed, that includes: Observation of a near-threshold enhancement in the Lambda Lambda-bar mass spectrum from e+ e- -> phi Lambda Lambda-bar at the center-of-mass energies from 3.51 to 4.60 GeV; Observation of e+ e- -> eta psi(2S) at the center-of-mass energies from 4.236 to 4.600 GeV; Cross section measurement of e+ e- -> p pbar eta and e+...
Nucleons are one of the most fundamental building blocks of ordinary matter, yet their internal structure and dynamics are still not fully understood. Electromagnetic form factors allow to investigate fundamental properties of the nucleon. The BESIII collaboration has studied the time-like form factors of the proton using the energy scan and the ISR technique. The |GE/GM| ratio is obtained...
We describe a simultaneous determination of unpolarized FFs of charged pions, charged kaons, and protons/antiprotons from single-inclusive hadron production in electron-positron annihilation (SIA) data at next-to-leading order and next-to-next-to-leading order accuracy in perturbative QCD. We include data for identified light charged hadrons as well as for unidentified light charged hadrons,...
Dileptons and photons are unique tools to study the space–time evolution of systems created by QCD in hadronic collisions. They are produced continuously by a variety of sources, in particular prompt and thermal photons and semileptonic heavy-flavour hadron decays, during the entire history of the collision and traverse the medium with negligible final state interaction. So they can carry...
The KLOE-2 experiment, at the $e^+e^-$ DA$\Phi$NE collider in Frascati, acquired an integrated luminosity of about 5 fb$^{-1}$ with an upgraded KLOE apparatus. The whole KLOE/KLOE-2 data sample corresponds to 2.4 $\times 10^{10} \,\phi$ and $3.1 \times 10^8 \,\eta$ meson events allowing to develop a wide hadron physics program from rare meson decays to $\gamma\gamma$ fusion and dark...
The spectroscopy of conventional hadrons containing a beauty quark is crucial to improve the knowledge of the non-perturbative regime of QCD. The LHCb experiment has been designed to study such hadrons and it is the ideal laboratory to search for as-yet-unobserved beauty baryons, including double heavy hadrons, and to perform precision measurements of already established hadrons. This talk...
Double parton scattering (DPS) is investigated using a states of a Z boson and jets, and of four jets, with CMS proton collisions data at 13 TeV. Final state distributions are studied as functions of several observables that exploit correlations between the jets, and the Z boson, with sensitivity to different aspects of the underlying event, parton shower, and matrix element calculations....
I would like to review recently introduced factorization called Improved Transverse Momentum Dependent factorization which applies in the regime of QCD when the saturation effects become relevant and when one has hard final state. Furthermore I would like to present an application of this formalism to phenomenological predictions of jet production in pA and eA.
The renormalization constant $Z_J$ of the flavor-singlet axial-vector current with a non-anticommuting $\gamma_5$ in dimensional regularization is determined to order $\alpha_s^3$ in QCD with massless quarks. The result is obtained by computing the matrix elements of the operators appearing in the axial-anomaly equation between the vacuum and a state of two (off-shell) gluons to 4-loop order....
We show how the polarized amplitudes of $b \bar{b} \rightarrow Z h$ associated with a non-vanishing $b$-quark Yukawa coupling and a scalar or pseudoscalar Higgs boson $h$ can be built up solely from vector form factors (FF) of properly grouped classes of diagrams, bypassing completely the need of explicitly manipulating $\gamma_5$ in dimensional regularization.
In addition, the FFs of a...
Over the last decade, the gradient flow formalism became an important tool for lattice simulations of Quantum Chromodynamics. Most prominently, scale setting strategies based on the gradient flow superseded previous strategies. Moreover, the gradient flow offers remarkable renormalization properties which pave the way for cross-fertilization between perturbative and lattice calculations.
In...
In the context of the PanScales parton shower project I will describe two advances in the development of final-state parton showers with controlled logarithmic accuracy. The first (arXiv:2011.10054) involves simple new algorithms to resolve the long-standing issue of incorrect subleading-colour contributions at leading logarithmic (LL) accuracy in dipole- and antenna-type showers, and also...
We present a detailed comparison of predictions computed by four publicly available computer codes for Drell-Yan processes at the LHC and Tevatron colliders. We point out that while there is agreement among the predictions at the next-to-leading order accuracy, the predictions at the next-to-next-to-leading order (NNLO) differ, whose extent depends on the observable. The sizes of the...
We calculate one loop scattering amplitudes for arbitrary number of positive helicity on-shell gluons and one off-shell gluon treated within the quasi-multi Regge kinematics. The result is fully gauge invariant and possesses the correct on-shell limit. Our method is based on embedding the off-shell process, together with contributions needed to retain gauge invariance, in a bigger fully...
The loop-tree duality (LTD) has become a novelty
alternative to bootstrap the numerical evaluation of
multi-loop scattering amplitudes.
It has indeed been found that Feynman integrands,
after the application of LTD, displays a representation
containing only physical information, the so-called
causal representation.
In this talk, I discuss the all causal representation
of...
Using $980 {\mathrm fb}^{−1}$ of data collected with the Belle detector, the two-photon process $\gamma\gamma \to \gamma\psi(2S)$ is studied for the first time in an effective center-of-mass energy ranging from $3.7$ to $4.2\,{\rm GeV}$. Evidence is established for a structure in the $\gamma\psi(2S)$ invariant-mass distribution at $3921.3 \pm 2.4 \pm 1.6\,{\rm MeV}$, and hint is found for...
In this poster we present the results of a lattice QCD comput-ation at $N_f = 2$ for the processes $B_{s} \rightarrow D_{s}^{(\star)}$, and their form factors parametrization in the heavy quark limit $\mathcal{G}$, $h_{A_{1}}$, $h_{A_{2}}$ and $h_{A_{3}}$. This study is in line with the research of new physics in the B sector, which is motivated by recent tensions reported in lepton flavor ...
Recent results of the study of double parton scattering with the CMS experiment using states of a Z boson and jets, and of four jets will be presented.
The accurate description of the internal structure of hadrons is a very challenging task. In order to compare the predictions with the highly-accurate experimental data, it is necessary to control any possible source of theoretical uncertainties. Thus, we can use the information extracted from final state measurement to constraint our knowledge about the internal structure of hadrons. In this...
We present first predictions of the cross sections and differential distributions for the exclusive reaction $pp \to pp K^{*0} \bar{K}^{*0}$ contributing to the $K^{+} K^{-} \pi^{+} \pi^{-}$ channel [1]. The amplitudes for the reaction are formulated within the tensor-pomeron approach [2]. We consider separately the $f_{2}(1950)$ $s$-channel exchange mechanism and the $K^{*0}$ $t/u$-channel...
Heavy-quark symmetry (HQS), despite being approximate, allows to relate dynamically many hadron systems.In the HQS-limit doubly-heavy baryons, whose dynamics is determined by a light quark moving in a color field of a static pair of heavy quarks, are similar to heavy mesons with a heavy antiquark being a color source. Non-local interpolation currents are introduced and corresponding matrix...
The reconstruction and calibration of hadronic final states is an extremely challenging experimental aspect of measurements and searches at the LHC. This talk summarizes the latest results from ATLAS for jet and missing energy reconstruction and calibration. New approaches to jet inputs better utilize relationships between calorimeter and tracking information to significantly improve the...
The differential cross section measurements of the production of a Drell-Yan pair of opposite-charged leptons (electrons or muons) as a function of pT and phi* in various bins of its invariant mass m as well as ratios of these cross sections to the on-shell one are presented. The results are obtained using proton-proton collision data recorded with the CMS detector at the LHC. Measurements are...
The cross sections of the Z boson production in association with at least two b jets as a function of various kinematic variables are measured in pp collisions at $\sqrt{s}$ = 13 TeV using 137 $\text{fb}^{-1}$ of data collected by the CMS experiment at LHC. The Z boson decays to electrons or muons are considered with leading (sub-leading) lepton transverse momentum $p_T$ > 35 (25) GeV and...
The R value, defined as the ratio of the inclusive hadronic cross section and the muon cross section in e+e- collisions, is an important input for the calculation of the Standard Model predictions of the anomalous magnetic moment of the muon a_mu and the running of the QED coupling constant alpha_QED(m_Z) evaluated at Z pole. The BESIII collaboration has collected data with high statistics to...
The Precision Proton Spectrometer (PPS) is a new subdetector of CMS introduced for the LHC Run 2, which provides a powerful tool for advancement of BSM searches.The talk will present the new results on exclusive diphoton, Z+X, and diboson production explored with with PPS, illustrating the unique sensitivity which can be achieved using proton tagging. The upcoming Run 3 will bring new...
We study the perturbative structure of threshold enhanced logarithms in the coefficient functions of deep inelastic scattering (DIS) and semi-inclusive $e^+ e^−$ annihilation (SIA) processes and setup a framework to sum them up to all orders in perturbation theory. Threshold logarithms show up as the distributions $((1−z)^{−1} log^i(1−z))_{+}$ from the soft plus virtual (SV) and as logarithms...
Good photon identification capabilities are important for many aspects of the ATLAS physics programme, including measurements of fundamental properties of the hard interaction in final states with one or more photons, possibly produced in association with jets or gauge bosons. The identification of prompt photons and the rejection of background coming mostly from photons from hadron decays...
The production of the $f_{0}(980)$ meson at high energies is not well understood. We investigate two different potential mechanisms for inclusive scalar meson production in the $k_t$-factorization approach: color-singlet gluon-gluon fusion and color evaporation model. The $\gamma^* \gamma^* \to f_0(980)$ form factor(s) can be constraint from the $f_0(980)$ radiative decay width. The $g^ g^...
The inclusive jet production cross sections and triple-differential cross sections of top quark-antiquark pair production at the LHC at a center of mass energy of 13 TeV are used together with data of inclusive deep inelastic scattering to extract the parton distributions of the proton and the strong coupling constant. In an additional analysis of the same data, the standard model cross...
Machine learning (ML) is pushing through boundaries in computational physics.
Jet physics, with it's large and detailed dataset, is particularly well suited.
In this talk will cover the work done in https://arxiv.org/abs/2104.01972
on the application of an unusual ML technique, Spectral Clustering, to jet formation.
Spectral clustering differers from much of ML as it has no "black-box"...
We perform Dalitz plot analysis of $\eta_c$ decays to $\eta^{\prime} K^+ K^-$, $\eta^{\prime} \pi^+ \pi^-$, and $\eta \pi^+ \pi^-$, where the $\eta_c$ is produced in two-photon interactions. We measure the parameters of $K^*_0(1430)$ and $K^*_0(1950)$ and observe production of $\sigma(600)$, $f_0(1400)$ and $f_0(1710)$ resonances. We observe new resonances decaying to $\pi^+ \pi^-$ in the...
We report on the measurement of the central exclusive production process $pp \ \rightarrow \ pXp$ in proton-proton collisions at RHIC with the STAR detector at $\sqrt{\mathrm{s}} = 510$ GeV. At this energy, this process is dominated by a double Pomeron exchange mechanism. The tracks of the centrally produced system $X$ were reconstructed in the central detector of STAR, the Time Projection...
We report the first measurement of exclusive cross sections for $e^{+}e^{-} \to B\bar{B}$, $e^{+}e^{-} \to B\bar{B}^{*}$, and $e^{+}e^{-} \to B^{*}\bar{B}^{*}$ in the energy range from $10.63$ to $11.02\,{\rm GeV}$. The $B$ mesons are fully reconstructed in a large number of hadronic final states, and the three channels are distinguished using the beam-energy-constrained mass variable. For...
Effective Field Theories such as HEFT, organized as momentum expansions, are a controllable approximation to strong dynamics only near threshold, as they miss exact elastic unitarity, reducing their predictive power at a higher scale if small separations from the Standard Model are found at the LHC orelsewhere. Unitarized chiral perturbation theory extends their reach to saturation of...
It is well-established that high-multiplicity pp and p–Pb collisions exhibit various signatures associated with the formation of QGP in heavy-ion collisions. In this contribution, we present results obtained using Underlying Event (UE) techniques, used to measure the average number density and the average total transverse momentum ($p_{\rm T}$) in the Toward, Transverse, and Away regions with...
Correlations between identified particles produced in high-energy nuclear collisions provide a wealth of information about hadronization mechanisms and the evolution of the system. New correlation measurements between long-lived particles (including $\pi$, K, p, $\Lambda$,$\Xi$) are used to investigate the particle production and the species dependence of (mini)jet fragmentation. The...
