Measurements of hard processes in heavy-ion collisions provide powerful and broad information on the dynamics of the hot, dense plasma formed in relativistic nucleus-nucleus collisions. This talk gives an overview of the latest jet measurements with the ATLAS detector at the LHC, utilizing the high statistics 5.02 TeV Pb+Pb data collected in 2015 and 2018. This talk presents multiple...
Light-flavor hadrons constitute the bulk of particle production in ultrarelativistic hadron-hadron collisions at the LHC. The measurements of the production of such particles are relevant to investigate the microscopic production mechanism of hadrons and to study collective effects in small collision systems. Among the light-flavor particles stemming from the hadronic collisions occurring at...
Due to the extremely large temperatures generated in ultra-relativistic heavy-ion collisions at the LHC, a state of matter known as the Quark-Gluon Plasma (QGP), where quarks and gluons are no longer confined within hadrons but exist in a deconfined state, is created. This phase transition occurs at around 170 MeV, and studies of the QGP aim to address fundamental questions related to the bulk...
The NA61/SHINE experimental physics program focuses on searching for the critical point and studying the properties of the onset of deconfinement in the strongly interacting matter. A two-dimensional scan is performed by varying the beam momentum (from 13\textit{A} to 150/158\textit{A} GeV/\textit{c}) and the system size (from $p$+$p$ to Pb+Pb) of the collided nuclei. This contribution will...
The CMS Zero Degree Calorimeters (ZDCs) are used to measure very forward and backward neutrons and photons from heavy-ion (and possibly pp) collisions at the LHC. Their purpose is to characterise the geometry of heavy ion, photon nucleus and photon-photon collisions. The ZDCs are built from layers of tungsten and quartz fiber and detect Cerenkov light produced by the showers of particles...
We present an improved parameterization of the elastic scattering of spin-0 particles, which is based on a dispersive
representation for the inverse scattering amplitude. Besides being based on well known general principles, the requirement that the
inverse amplitude should satisfy the dispersion relation significantly constrains its possible forms and have not been incorporated
in the...
In accelerator experiments, the production of light (anti)nuclei such as (anti)deuterons
and (anti)Helium can be studied in a wide range of collision systems from small
(pp) to large (A–A) emission source sizes. However, the microscopic mecha-
nism by which they are produced and how they survive such hot and turbulent
conditions is still unknown. The most commonly used models to describe...
The problem of confinement and the nature of the gluon are discussed in the framework of the screened massive expansion, a perturbative analytical approach to non-perturbative QCD.
After a brief review of the method, the main finding are outlined with some emphasis on the anlytic properties of the gluon propagator and on the nature of the complex conjugated poles.
Some conjectures are...
The last exotic spectroscopy discoveries and observations will be first shortly reviewed and then some of the main theoretical interpretations presented and discussed.
Finally, some results of which I am also one of the authors will be presented and discussed.
In this talk we shall summarise present status of the heavy baryon description within the Chiral Quark Soliton model, including exotica. We shall show that ground state parity + and excited parity - states are well described by the model. We shall argue that within the model some excitations are parametrically suppressed, so that the predicted spectrum is less abundant that in other...
The excellent performance of the LHCb experiment has opened
the road to precise hadron spectroscopy studies. A rich variety of new
resonances has already been discovered since last years. The very recent
LHCb results on pentaquark and tetraquarks are presented here.
The LHCb collaboration pursues a full physics program studying dense QCD with both beam-beam and fixed-target collisions. The forward design of the LHCb spectrometer allows probing the low-x region of the nucleus, while high vertexing precision and full particle ID guarantee the reconstruction of a wide range of hadrons down to very low transverse momentum. In this talk we present the recent...
The heavy quark momentum diffusion coefficient $\kappa$ is one of the most important ingredients for the Langevin description of the heavy quark dynamics. In the temperature regime relevant for the heavy ion collision phenomenology, a substantial difference exists between the lattice estimations of $\kappa$ and the corresponding leading order (LO) result from the hard thermal loop (HTL)...
We investigated the QCD phase diagram at large $N_c$ in a Polyakov loop extended quark-meson model with particular attention to the critical point(s). An exciting behavior was seen, as the well-known $N_c=3$ CEP disappears rapidly and leaves a crossover transition in the whole phase boundary. Furthermore, for large enough $N_c$, a distinct CEP emerges along the temperature axis. Moreover,...
We summarize recent results on the volume dependence of the location of the critical endpoint in the QCD phase diagram. To this end, we employ a
sophisticated combination of Lattice Yang--Mills theory and a (truncated)
version of Dyson--Schwinger equations in Landau gauge for $2 + 1$ quark
flavours. We study this system at small and intermediate volumes and
determine the dependence of the...
For more than two decades now, models of QCD such as the NJL model and quark-meson models have been showing that a specially inhomogeneous phase is favoured over the homogeneous one at high chemical potentials. Few studies, however, have attempted to show this within QCD itself. This is in part due to the fact that the usual stability analysis formalism had not yet been developed for QCD. In...
Abstract: Implicit Regularization (IReg) is a regularization scheme that works in the physical dimension of the theory and allows for the separation of the ultraviolet (UV) and infrared (IR) divergences of an amplitude. We compute the Higgs decay into gluons using an effective Higgs–Yang-Mills interaction in the limit of infinite top quark mass by using a dimension five operator. The decay...
In high-energy proton-nucleus (pA) collisions, an incoming energetic parton crosses the target nucleus and suffers medium-induced, fully coherent gluon radiation. I will briefly review the theoretical status of this effect, and present the phenomenological consequences of the corresponding fully coherent energy loss (FCEL) on hadron production in pA collisions at the LHC, and on the...
KLOE and KLOE-2 data are the largest dataset ever collected at an electron-positron collider operating at the $\phi$ resonance peak (almost 8 fb$^{-1}$).
The data corresponds to the production of about 24 billion of $\phi$ mesons, namely 8 billion pairs of neutral K mesons and 300 million $\eta$ mesons.
A wide hadron physics program, investigating rare meson decays, $\gamma\gamma$...
The NA62 experiment at CERN collected the world's largest dataset of charged kaon decays in 2016-2018, leading to the first measurement of the branching ratio of the ultra-rare K+ --> pi+ nu nu decay, based on 20 candidates.
The radiative kaon decay K+ → pi0e+vg (Ke3g) was studied with a data sample of O(100k) Ke3g candidates with sub-percent background contaminations recorded in 2017-2018....
I developed a mechanism where the final state interaction (FSI) within a CPT invariant two-channel framework can enhance the charge-parity (CP) violation difference between $D^0\to\pi^-\pi^+$ and $D^0\to K^-K^+$ decays up to the current experimental value.
%
This result relies upon:
(i) the dominant tree-level diagram,
(ii) the well-known experimental values for the $D^...
Recently, gravitational form factors (EMT-form factor) for nucleons has drawn attention in relation to internal structure of nucleons. It has been proposed that the EMT form factor can be interpreted as pressure or shear force distribution and its value at zero momentum transfer (the D-term) are required to be negative as a result of stability. In this talk, we show that for the most famous...
The idea of diquarks as effective degrees of freedom in QCD has been a successful concept in explaining certain low lying QCD states. Recently they have also played an important role in studying doubly heavy tetraquarks in phenomenology and on the lattice. The first member of this family of hadrons is the $T_{CC}$, newly discovered at LHCb. However, diquarks are colored objects and this has...
Recent relativistic heavy-ion collision experiments have found evidence for the generation of strong magnetic field and global angular momentum. The numerical simulation of evolution of the QCD medium is based on either magnetohydrodynamics or spin-hydrodynamics for calculation of observables pertaining to magnetic field or global angular momentum, respectively. However, these two effects are...
My MSc thesis involves the study of a map that links jet evolution to CGC (color glass condensate) evolution. In recent years, there has been a concerted effort to formalize the many similarities between jet evolution, which models high energy particle production experiments - and CGC evolution, which models high energy scattering experiments. To this end, a conformal map which establishes the...
Results on small collision systems are still under study to characterize whether a strongly interacting perfect fluid is formed or not. In this work we present an estimate of the initial state energy density on small collision systems. Results consider effects of initial state fluctuations on geometry and finite volume in a clusterization of color sources framework. The results are compared...
Hadronic resonances, due to their short lifetimes, are good probes to investigate the late-stage evolution of ultra-relativistic heavy ion collisions. Since they have lifetimes comparable to that of the fireball, the measured yields may be affected by rescattering and regeneration processes in the hadronic phase, which also modifies the particle's momentum distributions after hadronization....
In this talk we will discuss our recent works (2201.08253 and 2207.08563) in which we make analyses of several X and Z states. In the first part of the talk, we present a combined study of the BESIII spectra in which the Zc(3900) and Zcs(3985) states are seen, assuming that both are SU(3) partners. In the second part, a step further is taken and we analyze the full heavy quark spin and light...
I will review the traditional approach to heavy-light hadrons based on effective models of QCD and I will confront those old predictions for heavy-light hadrons (with the emphasis on exotica) with the recent developments based on string theory. The presentation exploits recent series of papers coauthored by me (Phys. Rev. D100 (2019)126023;
Phys.Rev. D104 (2021)114021; Phys. Rev. D104 (2021)...
In this contribution we present the main results of the calculations of spectra of meson and glueballs. To this aim the so called graviton soft-wall (GSW) has been used. This holographic semi-classic approximation to non perturbative QCD has been developed for the first time in Ref. [1] to calculate the scalar and tensor component spectra of glueballs. In particular we proposed to consider as...
Recently, JPAC collaboration has developed and benchmarked a systematic approach to use Deep Neural Networks as a model-independent tool to analyze and interpret experimental data and to determine the nature of an exotic hadron. Specifically, we studied the line shape of the Pc(4312) signal reported by the LHCb collaboration. This novel method presents great potential and can be applied to...
Belle II offers unique possibilities for the discovery and interpretation of exotic multiquark combinations to probe the fundamentals of QCD.
This talk present recent searches for the hidden bottom transition between Y(10750) and χbJ, as well as other results from an energy scan around 10.75 GeV.
The bottomonium spectrum is a perfect testing ground for the QCD confining potential and unitarisation effects. First of all, the bottom quark is about three times heavier than the charm quark, so that $b\bar{b}$ systems probe much more the short-range region of that potential. Secondly, the much smaller colour-hyperfine interaction in the $B$ meson makes the $B\bar{B}$ threshold lie...
The strong suppression of bottomonia in ultrarelativistic heavy-ion collisions is a smoking gun for the production of a deconfined quark-gluon plasma (QGP). In this talk, I will discuss recent work that aims to provide a more comprehensive and systematic understanding of bottomonium dynamics in the QGP. The new paradigm is based on an open quantum system approach applied in the framework of...
In Coulomb gauge QCD, there exists an instantaneous chromo-electric interaction between static quark-antiquark pairs. Studying this interaction is an effective way to probe aspects of quark confinement, as the confining behavior of this ‘Coulomb potential’ is related to the confining behavior of the Wilson potential in non-gauge fixed QCD. A clearer picture of the mechanism of confinement...
The spectroscopy of charmonium-like states together with the spectroscopy of charmed and strange baryons is discussed. It is a good testing tool for the theories of strong interactions, including: QCD in both the perturbative and non-perturbative regimes, LQCD, potential models and phenomenological models [1, 2, 3]. An understanding of the baryon spectrum is one of the primary goals of...
We review all the different direct and indirect approaches that lattice QCD has been employing to study multiquarks, focusing in the tetraquarks with heavy quarks. We also briefly review the experimental progress in observing tetraquarks, and the most representative models of tetraquarks, comparing them with the results of lattice QCD.
Since the discovery of quarks and the development of...
Within the use of framework of spectral Dyson-Schwinger equations three important QCD correlators will be presented: vacuum hadron polarization, pion transition form factor and the pion electromagnetic form factor. Future directions
will be discussed in my talk.
We investigate a representation of static quark operators based on trial states formed by eigenvector components of the covariant lattice Laplace operator. We test the method for computing the static quark-antiquark potential and compare the results to standard Wilson loop measurements. The runtime of the new method is significantly smaller when computing the static potential not only for...
Transport properties are hard to calculate from first
principles for any value of the coupling. At strong coupling, it's
generally considered impossible except for field theories with known
gravity duals. In this talk I will review large N approaches to simple
scalar and fermion field theories and show that they allow for the
determination of exact transport coefficients at strong...
