The new forward calorimeter, FoCal, extends the ALICE physics programme with the capability, unique at the LHC, of investigating gluon parton distribution functions (PDFs) down to Bjorken-x of ~10^-6. In this kinematic range, the gluon distributions are expected to behave non-linearly.
FoCal is a high-granularity forward calorimeter to be installed as an ALICE upgrade subsystem during the...
Ultraperipheral collisions (UPCs) of relativistic heavy ion beams lead to a diverse set of photon-nucleus (photonuclear) interactions. Measurements of particles produced in photonuclear reactions can shed light on the QCD dynamics of these novel, extremely asymmetric colliding systems, with energies between those available at RHIC and the LHC. Previous studies by ATLAS have characterized...
Understanding collectivity in small systems like proton-proton and proton-ion collisions remains a key challenge in heavy-ion physics. Recent LHC studies show signs of collectivity in high-multiplicity photonuclear collisions, where a quasi-real photon from one nucleus interacts with the other nucleus. In this talk, we present CMS measurements of two- and multi-particle correlations from...
Investigating collective behavior due to the formation of a fluid-like medium in small collision systems has been a significant focus in the field. A tell-tale signature of this would be the medium's response to the initial state in small collision systems, as predicted by fluid-dynamic models.
Recent RHIC studies of small systems have shown a hierarchy of elliptic anisotropy coefficients...
It is not understood how collective flow can occur in low-multiplicity systems such as minimum-bias proton-proton collisions. The problem is that these system appears to be too short lived to form equilibrated matter. To understand flow in these systems and the flow observed by ATLAS for UPC events, one typically need a flow mechanism that is not equilibrated.
In this talk, I discuss...
Ultra-peripheral heavy-ion collisions provide a unique laboratory for studying the structure of both nuclear and nucleon targets. In photonuclear interactions, the high-energy photons provided by the ultra-Lorentz boosted ions serve as a “femtoscope” for probing sub-femtoscale nuclear properties of the target, revealing details of the gluon distributions within nuclear matter. Substantial...
In this study, the production of strange particles is investigated in ultra-peripheral Pb–Pb collisions (UPCs) at $\sqrt{s_{\rm{NN}}}$ = 5.36 TeV, using data from the ALICE experiment at the LHC. The analysis focuses on selecting photo-nuclear reactions, where a quasi-real photon emitted by the fully ionized nucleus either acts as a point-like particle interacting with a parton in the...
In this talk, I will present our investigation of the T-odd nucleon energy correlator at small-x and elucidate its connection with spin-dependent odderons. The probe of this nucleon energy correlator involves measuring a single transverse spin asymmetry for the energy pattern in the deep inelastic scattering. We demonstrate that this asymmetry can be served as a clean and sensitive observable...
The Lorentz-boosted electromagnetic field surrounding relativistic heavy ions can be treated as a large flux of linearly polarized, quasi-real photons. The coherently photoproduced $J/\psi$ mesons inherit the linear polarization of these photons, leading to an azimuthal asymmetry in their decay products relative to the impact parameter. This asymmetry can be estimated using the second-order...
