Mon·Nov 28, 2022Monday·November 28, 2022

1. 01*

   Recent results on femtoscopic correlations with the CMS experiment

   Cesar A. Bernardes🇧🇷

   The study of femtoscopic correlations in high-energy collisions is a powerful tool to investigate the space-time structure of the particle emitting region formed in such collisions, as well as to probe interactions that the involved particles may undergo after being emitted. An overview of the recent results from the CMS experiment at the LHC on the two-particle femtoscopic correlations measurements using charged particles and identified hadrons in pp and PbPb collisions is presented. In general, the femtoscopic parameters are obtained assuming a Gaussian or an exponential shape to describe the emitting source distribution. In some cases, however, the generalized Gaussian, i.e., the symmetric alpha-stable Lévy distribution, is favored to describe the source. Some of the measurements allow to extract the parameters of the strong interaction felt by hadrons using their femtoscopic correlations. The studies are performed in a wide range of the pair average transverse momentum (or average transverse mass) and charged particle multiplicities. In addition, prospects for future physics results using the CMS experiment are also discussed.

   nucl-exPoS(2022)·1 citation
2. 02*

   Measurement of electrons from beauty-hadron decays in pp and Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

   ALICE Collaboration

   The production of electrons from beauty-hadron decays was measured at midrapidity in proton-proton (pp) and central Pb-Pb collisions at center-of-mass energy per nucleon-nucleon pair $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV, using the ALICE detector at the LHC. The cross section measured in pp collisions in the transverse momentum interval $2<p_{\mathrm{T}}<8$ GeV/$c$ was compared with models based on perturbative quantum chromodynamics calculations. The yield in the 10% most central Pb-Pb collisions, measured in the interval $2<p_{\mathrm{T}}<26$ GeV/$c$, was used to compute the nuclear modification factor $R_{\mathrm{AA}}$, extrapolating the pp reference cross section to $p_{\mathrm{T}}$ larger than 8 GeV/$c$. The measured $R_{\mathrm{AA}}$ shows significant suppression of the yield of electrons from beauty-hadron decays at high $p_{\mathrm{T}}$ and does not show a significant dependence on $p_{\mathrm{T}}$ above 8 GeV/$c$ within uncertainties. The results are described by several theoretical models based on different implementations of the interaction of heavy quarks with a quark-gluon plasma, which predict a smaller energy loss for beauty quarks compared to light and charm quarks.

   nucl-exhep-exPRC(2023)·15 citations
3. 03*

   System size and energy dependence of proton rapidity spectra from NA61/SHINE at the CERN SPS

   Oleksandra Panova🇵🇱 · Maciej Lewicki (for the NA61/SHINE collaboration)🇵🇱

   NA61/SHINE is an experiment at the CERN Super Proton Synchrotron. The main goals of the experiment are the search for the critical point of strongly interacting matter and the study of the properties of the onset of deconfinement. To reach these goals, the two-dimensional scan in beam momentum ($13A-150A$ GeV/$c$) and system size ($p$+$p$, Be+Be, Ar+Sc, Xe+La, Pb+Pb) was performed. In the final stage of the collision, the spectra of protons are only weakly affected by the effects of resonance decays and rescattering due to their large mass. Thus, proton rapidity distribution is particularly sensitive to the onset of deconfinement. This article presents experimental results on proton production in the collision energy range, which is most relevant to the onset of deconfinement. The procedure of measuring the proton rapidity spectra by NA61/SHINE is described, as well as Collaboration's recent results from reactions of $p$+$p$, Be+Be and Ar+Sc. Presented experimental results are confronted with existing data and models.

   nucl-exEPJ Web Conf.(2022)·5 citations
4. 04*

   Light (anti)nuclei production in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   The measurement of the production of deuterons, tritons and ${}^3\mathrm{He}$ and their antiparticles in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV is presented in this article. The measurements are carried out at midrapidity ($|y|<$ 0.5) as a function of collision centrality using the ALICE detector. The $p_{\mathrm{T}}$-integrated yields, the coalescence parameters and the ratios to protons and antiprotons are reported and compared with nucleosynthesis models. The comparison of these results in different collision systems at different centre-of-mass collision energies reveals a suppression of nucleus production in small systems. In the Statistical Hadronisation Model framework, this can be explained by a small correlation volume where the baryon number is conserved, as already shown in previous fluctuation analyses. However, a different size of the correlation volume is required to describe the proton yields in the same data sets. The coalescence model can describe this suppression by the fact that the wave functions of the nuclei are large and the fireball size starts to become comparable and even much smaller than the actual nucleus at low multiplicities.

   nucl-exhep-exPRC(2023)·51 citations
5. 05*

   First measurement of ${\Lambda }_{\mathrm{c}}^{+}$ production down to $p_{\mathrm{T}}=0$ in pp and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

   ALICE Collaboration

   The production of prompt ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}$ baryons has been measured at midrapidity in the transverse momentum interval $0<p_{\mathrm{T}}<1$ GeV/$c$ for the first time, in pp and p-Pb collisions at a centre-of-mass energy per nucleon-nucleon collision $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. The measurement was performed in the decay channel ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}\to \mathrm{p}{\mathrm{K}}_{\mathrm{S}}^0$ by applying new decay reconstruction techniques using a Kalman-Filter vertexing algorithm and adopting a machine-learning approach for the candidate selection. The $p_{\mathrm{T}}$-integrated ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}$ production cross sections in both collision systems were determined and used along with the measured yields in Pb-Pb collisions to compute the $p_{\mathrm{T}}$-integrated nuclear modification factors $R_{\mathrm{pPb}}$ and $R_{\mathrm{AA}}$ of ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}$ baryons, which are compared to model calculations that consider nuclear modification of the parton distribution functions. The ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}/{\mathrm{D}}^0$ baryon-to-meson yield ratio is reported for pp and p-Pb collisions. Comparisons with models that include modified hadronisation processes are presented, and the implications of the results on the understanding of charm hadronisation in hadronic collisions are discussed. A significant ($3.7\sigma$) modification of the mean transverse momentum of ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}$ baryons is seen in p-Pb collisions with respect to pp collisions, while the $p_{\mathrm{T}}$-integrated ${\mathrm{\Lambda }}_{\mathrm{c}}^{+}/{\mathrm{D}}^0$ yield ratio was found to be consistent between the two collision systems within the uncertainties.

   nucl-exhep-exPRC(2023)·62 citations
6. 06*

   J/$\psi$ production at midrapidity in p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV

   ALICE Collaboration

   The production of inclusive, prompt and non-prompt J/$\psi$ was studied for the first time at midrapidity ($-1.37<y_{\mathrm{cms}}<0.43$) in p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV with the ALICE detector at the LHC. The inclusive J/$\psi$ mesons were reconstructed in the dielectron decay channel in the transverse momentum ($p_{\mathrm{T}}$) interval $0<p_{\mathrm{T}}<14$ GeV/$c$ and the prompt and non-prompt contributions were separated on a statistical basis for $p_{\mathrm{T}}>2$ GeV/$c$. The study of the J/$\psi$ mesons in the dielectron channel used for the first time in ALICE online single-electron triggers from the Transition Radiation Detector, providing a data sample corresponding to an integrated luminosity of $689\pm 13\mu {\mathrm{b}}^{-1}$. The proton$-$proton reference cross section for inclusive J/$\psi$ was obtained based on interpolations of measured data at different centre-of-mass energies and a universal function describing the $p_{\mathrm{T}}$-differential J/$\psi$ production cross sections. The $p_{\mathrm{T}}$-differential nuclear modification factors $R_{\mathrm{pPb}}$ of inclusive, prompt, and non-prompt J/$\psi$ are consistent with unity and described by theoretical models implementing only nuclear shadowing.

   nucl-exhep-exJHEP(2023)·19 citations
7. 07*

   Rescattering effects on resonances production in small systems with ALICE at the LHC

   A. Rosano🇮🇹

   Recent multiplicity-dependent analyses of pp and p--Pb collision data have revealed that particle production shares similar features with that in heavy-ion collisions. Studies using resonances could help to understand the possible onset of collective-like phenomena and the presence of a hadronic phase in small collision systems. Measurements of the differential yields of resonances with different lifetime, mass, quark content, and quantum numbers could enable understanding the mechanisms that influence the shape of particle momentum spectra, lifetime of the hadronic phase, strangeness production, parton energy loss, and collective effects. New ALICE results on various hadronic resonances in small collision systems at Large Hadron Collider (LHC) energies, including the multiplicity dependence measurements of $\Lambda$(1520) and K${}^{\ast }$(892)${}^{\pm }$ and the production of $\varphi$-meson pairs are presented here. Results will be also compared with model calculations.

   nucl-exEPJ Web Conf.(2023)·0 citations
8. 08*

   Transuranium isotopes at ISAC/TRIUMF

   Peter Kunz🇨🇦 · Corina Andreoiu · Fatima H. Garcia🇨🇦 · Jens Lassen🇨🇦

   The production of transuranium isotopes has been demonstrated at the Isotope Separation and ACceleration (ISAC) facility. In particular a laser-ionized ${}^{239}$Pu beam, extracted from a uranium carbide target, was investigated. The experimental work was complemented by GEANT4 simulations, modelling the impact of secondary particles on the creation of transuranium isotopes through inelastic nuclear reactions. Theoretical production cross sections were derived and compared to experimental results, leading to a discussion on boundary conditions for the release of neptunium and plutonium from ISAC uranium carbide targets.

   nucl-exphysics.acc-phNucl.Instrum.Meth.B(2023)·3 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.