Session Z12: Mini-Symposium: The Upcoming Experimental Program at RHIC Run 23 and LHC Run 3

New Horizons for Jet and Heavy Flavor Measurements

TBD   

Multiplicity distributions from heavy-ion collisions at the Large Hadron Collider

Collisions of relativistic heavy ions at the Large Hadron Collider (LHC) are carried out in order to create a unique state of matter known as the Quark Gluon Plasma (QGP). In this state, hadronic matter melts, and quarks and gluons become the relevant degrees of freedom. It is believed that the universe temporally existed in such a state shortly after the big bang. The distribution of produced charged particles (multiplicity) provides critical information regarding the initial state of these collisions. I will present the latest multiplicity distributions and mean transverse momentums measured by the ALICE collaboration at the LHC. I will discuss comparisons of these distributions to theoretical models, the measurements of the speed of sound experimentally and detail future plans regarding new measurement techniques.   

Centrality bias study for charged-particle nuclear modification factor in pPb and PbPb collisions using the ANGANTYR model at √(SNN)=5.02 TeV

Relativistic heavy ion collisions of sufficiently high energy produce quark-gluon plasma (QGP). QGP dynamics can be described macroscopically using hydrodynamics. Medium effects on the production of high-p_T particles in nucleus-nucleus (AA) collisions are generally quantified by the charged particle nuclear modification factor (R_AA), defined to be unity in the absence of nuclear effects. Using the ANGANTYR model, we ignore the macroscopic behavior of QGP and instead directly extrapolate high energy pp collisions to heavy ion collisions. With this model we study R_AA in PbPb and pPb collisions at √(S_NN)=5.02 TeV. Despite the exclusion of medium effects, we find reduced R_AA across centrality bins, consistent with CMS data.   

Multiplicity dependence of the $\Lambda_{\rm c}/\rm {D^{0}}$ yield ratio in small systems with ALICE

The measurement of charm baryon-to-meson yield ratio is sensitive to the hadronization processes and it can be used as a tool to investigate baryon and meson formation.  Recent measurements performed by ALICE in pp collisions showed an increase of these ratios with respect to measurements performed in $\rm{e^{+}e^{-}}$ collisions.   Similar features as those observed in Pb--Pb collisions have been recently observed in high-multiplicity pp collisions.  A systematic study of the $\rm {\Lambda_{c}/D^{0}}$ from very low to high multiplicity in small systems provides tools to investigate these aspects.  

In this contribution, the study of the $\rm {\Lambda_{c}/D^{0}}$  in different multiplicity intervals in pp collisions at  $\sqrt{s}=$~13 TeV  and p--Pb collisions at $\sqrt{s_{\rm{NN}}}=~5.02$ TeV are discussed. The measurements are compared with theoretical predictions, with different hadronization models.    

Properties of multiple charmonium production at CMS

CMS experiment collected large dataset with charmonium triggers from 2016 to 2018, corresponding to an integrated luminosity of about 135 fb-1. This large dataset provides us a test ground to investigate the production mechanism of several charmonium states in one pp collision. The latest results on this topic will be reported.   

Recent results and prospects on semileptonic b decays from LHCb

Semileptonic decays of the beauty hadrons provide a platform to study the fundamental Standard Model parameters and reveal the potential New Physics contributions. Semileptonic b decays take high branching fractions and clean theoretical inputs, resulting in more precise measurements to be expected. At LHCb the studies on semileptonic b decays come with challenges, including the significant background contributions from the missing nuetrino and partially reconstructed decays and the higher reliance on simulation. Therefore specialization analysis strategies are required for the studies of semileptonic b decays at LHCb.

In this presentation, recent studies on semileptonic b decays at LHCb will be reported, including the measurements of the fundamental quark mixing parameter V_cb, the measurements of  the semileptonic asymmetry in B⁰/B_s semileptonic decays, and studies of the lepton universality. Besides, the prospects of measuremnts of semileptonic b decays at LHCb in the future will be discussed.   

A Soft Particle Tracker in LHCb For Gluon Saturation Studies

One of the most exciting features of Quantum Chromodynamics is the possibility to observe gluon saturated matter. This state of matter would be a strong force condensate, much like the Bose-Einstein Condensates observed at the atomic level. In order to observe the effect of saturated gluons in particle colliders, the detector must be able to measure soft particles in the forward direction relative to the beam. The LHCb experiment at LHC is an excellent candidate to detect this phenomenon. A soft particle tracker, The Magnet Station, has been designed to be installed in the LHCb magnet. This device has the capability to access particles coming from the expected gluon saturation region. The physics and detector concepts along with the status of the detector development will be presented.   

Collisional Energy Loss and the Chiral Magnetic Effect

Collisional energy loss of a fast particle in a medium is mostly due to the medium polarization by the electromagnetic fields of the particle. In addition to Cherenkov radiation, in a chiral medium there is a contribution to the energy loss mostly in the form of chiral Cherenkov radiation due to induction of the anomalous current proportional to the magnetic field. We employ classical electrodynamics to compute the collisional energy loss by a fast particle in a homogenous chiral plasma and apply the results to quark-gluon plasma and a Weyl semimetal. In Weyl semimetals, the photon spectrum is strongly enhanced in the ultraviolet and x-ray regions which makes it amenable to experimental investigation. Our main observation is that while the collisional energy loss in a nonchiral medium is a slow, at most logarithmic, function of energy ɛ, the chiral Cherenkov radiation is proportional to ɛ^2 when the recoil is neglected and to ɛ when it is taken into account.