Publications

Order by: publication date number of citations

Sub-TeV hadronic interaction model differences and their impact on air showers

Michael Schmelling, Álvaro Pastor-Gutiérrez, Harm Schorlemmer, Robert Daniel Parsons

SciPost Phys. Proc. 15, 015 (2024) · published 2 April 2024 | · pdf

In the sub-TeV regime, the most widely used hadronic interaction models disagree significantly in their predictions of particle spectra from cosmic ray induced air showers. We investigate the nature and impact of model uncertainties, focussing on air shower primaries with energies around the transition between high and low energy hadronic interaction models, where the dissimilarities are largest and which constitute the bulk of the interactions in air showers.
The role of the underlying event in the charm-baryon enhancement observed in pp collisions at LHC energies

Zoltán Varga, Anett Misák, Róbert Vértesi

SciPost Phys. Proc. 15, 014 (2024) · published 2 April 2024 | · pdf

We study the enhanced production of $\Lambda_c$ charmed baryons relative to that of charmed $D^0$ mesons in proton–proton collisions at LHC energies. We simulated collision events with the enhanced color-reconnection model in PYTHIA 8 MC generator and propose measurements based on the comparative use of different event-activity classifiers to identify the source of the charmed-baryon enhancement. We demonstrate that in this enhanced color-reconnection scenario the excess production is primarily linked to the underlying event and not to the production of high-momentum jets.
ATLAS results on exotic hadronic resonances

Yue Xu

SciPost Phys. Proc. 15, 013 (2024) · published 2 April 2024 | · pdf

Recent results from the proton-proton collision data taken by the ATLAS experiment on exotic resonances are presented. A search for $J/\psi p$ resonances in $\Lambda_{b}→ J/\psi p K$ decays with large $p K$ invariant masses is reported. A search for exotic resonances in the four-muon final state is shown.
Intermittency analysis of charged particles generated in Xe-Xe~collisions at $\sqrt{s_{\rm{NN}}}$ = 5.44 TeV using the AMPT model

Zarina Banoo, Ramni Gupta

SciPost Phys. Proc. 15, 010 (2024) · published 2 April 2024 | · pdf

The multiplicity fluctuations are sensitive to QCD phase transition and to the presence of critical point in QCD phase diagram. At critical point a system undergoing phase transition is characterized by large fluctuations in the observables which is an important tool to understand the dynamics of particle production in heavy-ion interactions and phase changes. Multiplicity fluctuations of produced particles is an important observable to characterize the evolving system. Using scaling exponent obtained from the normalized factorial moments of the number of charged hadrons in the two dimensional ($\eta,\phi$) phase space, one can learn about the dynamics of system created in these collisions. Events generated using Xe-Xe collisions at $\sqrt{s_{\rm{NN}}} = 5.44 $ TeV with string-melting (SM) version of the AMPT model are analyzed and the scaling exponent $(\nu)$ for various $p_T$ intervals is determined. It is observed that the calculated value of $\nu$ is larger than the universal value 1.304, as is obtained from Ginzburg-Landau theory for second order phase transition. Here we will also present the results of the dependence of the scaling exponent on the transverse momentum bin width.
Physics motivation and detector upgrades for the new era of the ATLAS experiment

Jason Nielsen

SciPost Phys. Proc. 8, 126 (2022) · published 13 July 2022 | · pdf

The ATLAS experiment at CERN’s Large Hadron Collider (LHC) will be upgraded in two stages to prepare first for the Run 3 data-taking campaign, during which the integrated luminosity will roughly double, and then for the High-Luminosity LHC program with an ultimate integrated luminosity of up to 4 ab-1. These upgrades and high-statistics datasets will allow ATLAS to perform searches and precision measurements to constrain the Standard Model in yet-unexplored phase spaces and in the Higgs sector. This contribution summarizes the ATLAS detector upgrades and selected physics prospects for Run 3 and the HL-LHC.
Longitudinal and Transverse Spin Transfer of $Λ$ and $\overlineΛ$ Hyperons in Polarized $p$+$p$ Collisions at $\sqrt{s} = 200$ GeV at RHIC-STAR

Yike Xu

SciPost Phys. Proc. 8, 125 (2022) · published 13 July 2022 | · pdf

Measurements of the longitudinal spin transfer, $D_{LL}$, and the transverse spin transfer, $D_{TT}$, of the $\Lambda(\bar{\Lambda}$) hyperon in polarized $p$+$p$ collisions are expected to be sensitive to the helicity distribution and transversity distribution of the $s(\bar{s})$ quark in proton and the corresponding polarized fragmentation functions. This contribution presents the new preliminary results of the $\Lambda(\bar{\Lambda}$) $D_{LL}$ and $D_{TT}$ using data collected at RHIC-STAR experiment in 2015, with twice larger statistics than previously published results.
Towards the computation of inclusive decay rates using lattice QCD

Paolo Gambino, Shoji Hashimoto, Sandro Mächler, Marco Panero, Francesco Sanfilippo, Silvano Simula, Antonio Smecca, Nazario Tantalo

SciPost Phys. Proc. 15, 004 (2024) · published 2 April 2024 | · pdf

We present a non-perturbative computation of inclusive rates of semileptonic decays of heavy mesons from lattice QCD simulations. The calculation is based on the extraction of smeared spectral functions obtained from four-point Euclidean correlation functions computed on configuration ensembles of the JLQCD and ETM collaborations. We compare our results for the inclusive decay rates with analytical predictions from the operator-product expansion, finding a good agreement for the calculation of the inclusive decay rate. This opens the path to the theoretical determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element $V_{cb}$ to a level of precision competitive with the present experimental uncertainty.
Measurement of the $t\bar{t}t\bar{t}$ production at 13 TeV with the ATLAS detector at the LHC

Ö. Ogul Öncel

SciPost Phys. Proc. 8, 116 (2022) · published 13 July 2022 | · pdf

Two measurements and their combination for the $t\bar{t}t\bar{t}$ production cross-section analysis using 139 fb$^{-1}$ of proton$-$proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the LHC are presented. The first analysis uses the final states with either one or two opposite-sign leptons (electrons or muons). In the second analysis the final states with either two same-sign or at least three leptons are considered. With an observed (expected) significance of 4.3 (2.4) standard deviations over the background-only hypothesis, the second analysis provides the first evidence for the $t\bar{t}t\bar{t}$ process. No significant deviations from the Standard Model are observed.
Anomalous coupling studies with forward protons at the LHC

C. Royon

SciPost Phys. Proc. 8, 115 (2022) · published 13 July 2022 | · pdf

We describe the gain on sensitivities to quartic $\gamma \gamma \gamma \gamma$, $\gamma \gamma WW$ and $\gamma \gamma \gamma Z$ anomalous couplings and to the search for Axion-Like Particles by two or three orders of magnitude with respect to standard methods at the LHC by tagging intact protons in the final state.
Measurements of $t\overline{t}$ production cross-sections with the ATLAS experiment at the LHC

Margherita Spalla

SciPost Phys. Proc. 8, 112 (2022) · published 13 July 2022 | · pdf

Comprehensive measurements of differential cross-sections of top-quark-antiquark pair-production are presented. They are performed in the dilepton, lepton+jets and the all-hadronic channels, using $\sqrt{s}=13$ TeV data from the ATLAS detector at the LHC. Several setups of next-to-leading order and next-to-next-to-leading order generators are quantitatively compared to the measurements. In addition, total cross-section measurements using up to the full ATLAS Run 2 dataset are presented.

Previous 1 ... 54 55 56 57 58 59 60 61 62 63 64 ... 75 Next