Publications

Order by: publication date number of citations

• Precision physics with the proton spectrometer and diffractive physics measurements from CMS

  Cristophe Royon

  SciPost Phys. Proc. 15, 030 (2024) · published 3 April 2024 | Toggle abstract · pdf

  We describe recent results from CMS and TOTEM on hard diffraction, diffractive jets and jet gap jet events. We also give the first sensitivities and limits on quartic anomalous couplings and axion-like particles at high mass using the LHC as a $\gamma \gamma$ collider. The predicted sensitivities with 300 fb$^{-1}$ are better by two or three orders of magnitude compared to the more standard methods at the LHC without measuring intact protons after collision.

• Anomalous coupling studies with intact protons at the LHC

  Cristophe Royon

  SciPost Phys. Proc. 15, 029 (2024) · published 3 April 2024 | Toggle abstract · pdf

  We describe the reaches on quartic $\gamma \gamma \gamma \gamma$, $\gamma \gamma WW$, $\gamma \gamma ZZ$, $\gamma \gamma \gamma Z$, $\gamma \gamma t \bar{t}$ anomalous couplings at the LHC using intact protons in the final state measured in AFP in ATLAS or PPS in CMS-TOTEM.

• An overview of lattice results for parton distribution functions

  Luigi Del Debbio

  SciPost Phys. Proc. 15, 028 (2024) · published 3 April 2024 | Toggle abstract · pdf

  Following a ground-breaking proposal by Ji [Phys. Rev. Lett. 110, 262002 (2013)], numerical simulations of Quantum Chromo Dynamics (QCD) on a Euclidean lattice have provided new, valuable information on the structure of hadrons. In this talk, we briefly review the lattice approach to the reconstruction of parton densities, highlighting the connection between lattice observables and parton densities, with a focus on theoretical issues. Since parton distributions are extracted from lattice data by solving an inverse problem, we discuss some of the difficulties that affect these determinations and how they can be formulated in a Bayesian framework.

• Λ(1520) resonance production with respect to transverse spherocity using EPOS3+UrQMD

  Nasir Mehdi Malik, Sanjeev Singh Sambyal

  SciPost Phys. Proc. 15, 027 (2024) · published 3 April 2024 | Toggle abstract · pdf

  Resonances are sensitive to the properties of the medium created in heavy ion collision. They also provide insight into the properties of the hadronic phase. Studying the dependence of the yield of resonances on transverse spherocity and multiplicity allows us to understand the resonance production mechanism with event topology and system size, respectively. The results reported pertain to $\Lambda(1520)$, using predictions from EPOS3+UrQMD event generator.

• Hyperon physics at BESIII

  Viktor Thorén

  SciPost Phys. Proc. 15, 026 (2024) · published 3 April 2024 | Toggle abstract · pdf

  Spin polarization and entanglement are utilized by the BESIII experiment to learn more about the production and decay properties of hyperon-antihyperon pairs in a series of recent analyses of its unprecedented datasets at the $J/\psi$ and $\psi'$ resonances. This has lead to the observation of significant transverse polarisation in decays of $J/\psi$ or $\psi'$ into $\Lambda \bar{\Lambda}$, $\Sigma \bar{\Sigma}$, $\Xi \bar{\Xi}$, and $\Omega \bar{\Omega}$. Because of the non-zero polarization, the decay parameters for the most common hadronic weak decays of both hyperons and antihyperons could be determined independently for the first time. Comparing these to each other yields precise tests of direct, $\Delta S = 1$ CP-violation that complement measurements of kaon decays.

• How the blast-wave model describes PID hadron spectra from 5 TeV p-Pb collisions

  Thomas A. Trainor

  SciPost Phys. Proc. 15, 025 (2024) · published 3 April 2024 | Toggle abstract · pdf

  The blast-wave (BW) spectrum model has been applied extensively to nucleus-nucleus collision data with the intention to demonstrate formation of a quark-gluon plasma (QGP) in more-central A-A collisions. More recently the BW model has been applied to p-p, d-Au and p-Pb collisions. Such results are interpreted to indicate that "collectivity" (flows) and QGP appear in smaller systems. In this talk I review BW analysis of identified-hadron spectra from 5 TeV p-Pb collisions and examine the shape evolution of model spectra with collision centrality. I evaluate data-model fit quality using conventional statistical measures. I conclude that the BW model is not a valid data model.

• Centrality dependence of multistrange baryon production in high-energy heavy-ion collisions

  Gevorg H. Arakelyan, Carlos Merino, Yuli M. Shabelski

  SciPost Phys. Proc. 15, 024 (2024) · published 3 April 2024 | Toggle abstract · pdf

  We consider the experimental data on the production of strange $\Lambda^{\prime}$s, and multistrange baryons ($\Xi$, $\Omega$), and antibaryons, on nuclear targets, at the energy region from SPS up to LHC, in the framework of the Quark-Gluon String Model. One remarkable result of this analysis is the significant dependence on the centrality of the collision of the experimental $\overline{\Xi}^+/\overline{\Lambda}$ and $\overline{\Omega}^+/\overline{\Lambda}$ ratios in heavy-ion collisions, at SPS energies.

• Helix string fragmentation and charged particle correlations with ATLAS

  Šárka Todorova-Nová

  SciPost Phys. Proc. 15, 023 (2024) · published 3 April 2024 | Toggle abstract · pdf

  Correlations between charged particles provide important insight into the hadronization process. The analysis of the momentum difference between charged hadrons in pp, p-lead, and lead-lead collisions at LHC is performed by the ATLAS Collaboration in order to study the dynamics of hadron formation. The spectra of correlated hadron chains are explored and compared to the predictions based on the quantized fragmentation of a three dimensional QCD helix string. This provides an alternative view of the two-particle correlation phenomenon typically attributed to the Bose-Einstein interference.

• All order merging of high energy and soft collinear resummation

  Jeppe R. Andersen, Hitham Hassan, Sebastian Jaskiewicz

  SciPost Phys. Proc. 15, 022 (2024) · published 3 April 2024 | Toggle abstract · pdf

  We present a method of merging the exclusive LO-matched high energy resummation of High Energy Jets (HEJ) with the parton shower of PYTHIA which preserves the accuracy of the LO cross sections and the logarithmic accuracy of both resummation schemes across all of phase space. Predictions produced with this merging prescription are presented with comparisons to data from experimental studies and suggestions are made for further observables and experimental cuts which highlight the importance of both high energy and soft-collinear effects.

• All about the neutron from lattice QCD

  Rajan Gupta

  SciPost Phys. Proc. 15, 021 (2024) · published 3 April 2024 | Toggle abstract · pdf

  I describe how simulations of lattice QCD using the path integral formulation provide the two basic quantum mechanical properties of QCD, its ground state in which correlation functions are calculated, and Fock state wavefunctions between which matrix elements of operators are calculated. Both constructs are stochastic, so unfortunately one gets no intuitive picture or even qualitative understanding of what they look like, nevertheless they contain and display all the subtleties of the quantum field theory. Today, these simulations provide many quantities that are impacting phenomenology and experiments. I illustrate the methods and the steps in the analysis using, as examples, three observables: the isovector charges of the nucleon, the contribution of the quark's intrinsic spin to the nucleon spin, and the pion-nucleon sigma term.