Related papers: Some physics of small collision systems
The small collision systems like p+p and p+A collisions have shown new features like A+A collisions in the relativistic regime. These new aspects in small systems which have altered our research and understanding on the two-particle…
Two particle correlations have been used extensively to study hydrodynamic flow patterns in heavy-ion collisions. In small collision systems, such as $p$$+$$p$ and $p$$+$$A$, where particle multiplicities are much smaller than in $A$$+$$A$…
For the past decade, measurements of semi-inclusive single identified particle spectra and two particle correlations in p-p and A+A collisions at RHIC have produced a treasure trove of results which indicate that the medium produced in…
Identified-hadron (PID) $p_t$ spectra from 13 TeV $p$-$p$ collisions are compared with a two-component (soft+hard) model (TCM) that accurately distinguishes jet-related hadron production (hard component) from nonjet projectile-nucleon…
In heavy-ion collisions at the LHC a hot and dense medium of deconfided partons, the Quark-Gluon Plasma (QGP), is created. Its global properties can be characterized by the measurements of particles in the low transverse momentum (or…
A nontrivial space-time structure of the hot system created at RHIC is the defining aspect of the physics of relativistic heavy ion collisions. Femtoscopy through pion intensity interferometry provides direct access to the dynamic geometric…
In p-p collisions, the produced charge particles consist of two leading particles and those frozen out from the hot and dense matter created in collisions. The two leading particles are respectively in the projectile and target…
We present the first full (3+1)D dynamical simulations of ultra-peripheral Pb+Pb collisions at the Large Hadron Collider. Extrapolating from p+Pb collisions, we explore whether a quasi-real photon $\gamma^*$ interacting with the lead…
Relativistic heavy ion collisions produce nuclei-sized droplets of quark-gluon plasma whose expansion is well described by viscous hydrodynamic calculations. Over the past half decade, this formalism was also found to apply to smaller…
Two-particle correlations in relative rapidity and azimuth are studied for the p-Pb collisions at the LHC energy of 5.02 TeV in the framework of event-by-event 3+1-dimensional viscous hydrodynamics. It is found that for the…
An attempt has been made to estimate the minimum size of the de-confined matter of Quark-Gluon Plasma (QGP) in small systems like p-Pb system that could be satisfactorily modeled with low-order hydrodynamics. The variation of second order…
The field of heavy ion physics is at a crossroads in understanding experimental signatures of collectivity in small collision systems, p + p and p(d/3He) + A, at RHIC and the LHC. A wealth of data obtained in the latter class of asymmetric…
We scrutinize the recent LHCb data for D$^0$-meson production in p+Pb collisions within a next-to-leading order QCD framework. Our calculations are performed in the SACOT-$m_{\rm T}$ variant of the general-mass variable-flavour-number…
Collectivity, as interpreted to mean flow of a dense medium in high-energy A-A collisions described by hydrodynamics, has been attributed to smaller collision systems -- p-A and even p-p collisions -- based on recent analysis of LHC data.…
Measurements of event-ensemble mean transverse momentum $\langle p_t \rangle$ vs charged-hadron multiplicity $n_{ch}$ for $p_t$ spectra from 5 TeV p-Pb and 2.76 TeV Pb-Pb collisions and from p-p collisions for several energies have been…
This overview focusses on recent developments, in the most part triggered by LHC data, aimed at the development of a reliable and complete theoretical description of high-p$_t$ physics in heavy ion collisions. Particular emphasis is placed…
The energy density is the prime parameter to define the deconfinement of quarks and gluons occurring in collisions of heavy ions. Recently, there is mounting evidence that many observables in proton-proton collisions behave in a manner very…
From a recently found family of analytic, finite and accelerating 1+1-dimensional solutions to perfect fluid relativistic hydrodynamics, we derive simple and powerful formulae to describe the rapidity and pseudorapidity density…
One of the most remarkable observations in heavy-ion collisions is the systematic regularity exhibited by pseudorapidity distributions of charged particles across collision energies. While single-source models fail at higher energies and…
The first measurement of pseudorapidity and azimuthal angle distributions relative to the momentum vector of a Z boson for low transverse momentum ($p_\mathrm{T}$) charged hadrons in lead-lead (PbPb) collisions is presented. By studying the…