Prospects for strangeness production in pp collisions at the Large Hadron Collider (LHC) are discussed within the statistical model. Firstly, the system size and the energy dependence of the model parameters are extracted from existing data and extrapolated to LHC energy. Particular attention is paid to demonstrate that the chemical decoupling temperature is independent of the system size. In the energy regime investigated so far, strangeness production in pp interactions is strongly influenced by the canonical suppression effects. At LHC energies, this influence might be reduced. Particle ratios with particular sensitivity to canonical effects are indicated.
Secondly, the relation between the strangeness production and the charged-particle multiplicity in pp interactions is investigated. In this context the multiplicity dependence studied at Tevatron is of particular interest. There, the trend in relative strangeness production known from centrality dependent heavy-ion collisions is not seen in multiplicity selected pp interactions. However, the conclusion from the Tevatron measurements is based on rather limited data samples with low statistics and number of observables. We argue, that there is an absolute need at LHC to measure strangeness production in events with different multiplicities to possibly disentangle relations and differences between particle production in pp and heavy-ion collisions.
We briefly recollect the problem of significant hyperon polarization emphasizing the role of spin in dynamics of hadron interactions. We provide also some model predictions based on chiral dynamics and the impact parameter picture for illustration. The old, but yet unsolved problem of hyperon polarization, can obtain a new insight from the measurements at the LHC energies and, in combination with other measurements, can be used for tagging QGP formation in $pp$--collisions.
The p$-$p collisions at high multiplicity at LHC show small scale collective effects similar to that observed in heavy ion collisions such as enhanced production of strange and multi-strange hadrons, long range azimuthal correlations, etc. The observation of strangeness enhancement in p$-$p collisions at at $\sqrt{s}$ = 7 TeV and 13 TeV as measured by ALICE experiment is explored using Pythia8 event generator within the framework of microscopic rope hadronization model which assumes the formation of ropes due to overlapping of strings in high multiplicity environment. The transverse momentum (…
The strangeness enhancement signature of QGP formation at LHC energies is carefully tackled in the present study. Based on HRG, the particle ratios of mainly strange and multi-strange particles are studied at energies from lower $\sqrt{s}\sim $ 0.001 up to 13 TeV. The strangeness enhancement clearly appeared at more higher energies, and the ratios are confronted to the available experimental data. The particle ratios are also studied using the Cosmic Ray Monte Carlo (CRMC) interface model with its two different event generators namely; EPOS $1.99$ and EPOSlhc which show a good agreement with t…
We present an analysis of data on light flavour hadron production as function of event multiplicity at LHC energies measured by the ALICE collaboration. The strangeness-canonical approach within the framework of the THERMUS statistical hadronisation model is used for a simultaneous description of pp, p-Pb, and Pb-Pb collisions. The rapidity window dependence of the strangeness correlation volume is addressed and a value of $Δy = 1.33 \pm 0.28$ is found. With the exception of the $ϕ$-meson, an excellent description of the experimental data is found.
We present a modification to the non-perturbative strangeness production mechanisms in the Monte-Carlo event generator Herwig in order to make the processes more dynamic and collective. We compare the model to a series of observables for soft physics at both LEP and LHC.
We present novel rope hadronization results for strange hadron enhancement in pp, pPb, and PbPb collisions using PYTHIA/Angantyr at LHC energies. With the rope model for string fragmentation, we find that the strangeness and baryon enhancement has a coherent increase across all collision systems as a function of average charged central multiplicity, in qualitative agreement with LHC data. In AA collisions, we find that the baryonic yields overshoot data at high multiplicities, and we discuss how a combination of rope hadronization with other string interactions may tame this rise.
Experimental observations of extensive air showers have revealed an excess of the muon content with respect to their theoretical simulations, which we refer to as the muon puzzle. This muon puzzle hampers a precise determination of the ultra-high-energy cosmic ray mass composition. We investigate the potential of producing states of dense quark-gluon matter (which we call fireballs) to resolve the muon puzzle as quantified with data from the Pierre Auger Observatory on the depth of the shower maximum and the number of muons at ground. Adopting a phenomenological fireball model, we find that th…
We briefly review the status of high precision QCD predictions available for LHC processes, focusing on corrections beyond NLO and ways to make the latter available in a convenient format. As a phenomenological example we discuss the two-loop corrections to Higgs boson pair production in gluon fusion.
We investigate whether the quark gluon plasma (QGP) is created in small colliding systems from analyses of various hadron yields and their ratios in proton-proton (p+p), proton-lead (p+Pb) and lead-lead (Pb+Pb) collisions at LHC energies. Recently, the ALICE Collaboration reports enhancement of yield ratio of multi-strange hadrons to charged pions as a function of multiplicity at mid-rapidity. Motivated by these results, we develop the dynamical core-corona initialization framework and find that our results describe tendencies of the ALICE data especially for multi-strange hadrons. These resul…
In the hadrocharmonium picture a $\bar cc$ state and a light hadron form a bound state. The effective interaction is described in terms of the chromoelectric polarizability of the $\bar cc$ state and energy-momentum-tensor densities of the light hadron. This picture is justified in the heavy quark limit, and may successfully account for a hidden-charm pentaquark state recently observed by LHCb. In this work we extend the formalism to the description of hidden-charm tetraquarks, and address the question of whether the resonant states observed by LHCb in the $J/ψ$-$ϕ$ spectrum can be described a…
An experimental overview of the energy dependence of strangeness production is presented. The strange hadrons are considered a good probe to study the QCD matter created in relativistic nucleus-nucleus collisions. The heavy-ion experiments at SPS, RHIC, and LHC have recorded a wealth of data in proton-proton, proton-nucleus and nucleus-nucleus collisions at several beam energies. In this proceeding, I discuss the invariant yield and azimuthal anisotropy measurement of strange hadrons in nucleus-nucleus collisions at SPS, RHIC, and LHC.
We have estimated centrality variation of chemical freeze-out parameters from yield data at mid-rapidity of $π^\pm$, $K^\pm$ and $p$, $\bar{p}$ for collision energies of RHIC (Relativistic Heavy Ion Collider), Beam Energy Scan (RHIC-BES) program, and LHC (Large Hadron Collider). We have considered a simple hadron resonance gas model and employed a formalism involving conserved charges ($B, Q, S$) of QCD for parameterization. Along with temperature and three chemical potentials ($T,μ_B,μ_Q,μ_S$), a strangeness under-saturation factor ($γ_S$) has been used to incorporate the partial equilibratio…
Hadron colliders are providing a unique opportunity for testing Lorentz invariance and CPT symmetry at high energy and in a laboratory. A first measurement in the top-quark sector was performed at the Tevatron. We present here prospective studies for testing Lorentz invariance in top-quark pair production at the LHC and future colliders. The b-quark sector was investigated recently at LHCb. Eventually, new bounds on photon parameters can be extracted from the observation of TeV photons at the LHC. We will conclude by highlighting other opportunities provided by hadron colliders.
This paper investigates a signature of Lorentz invariance violation with the $t\bar{t}$ production at the LHC and future hadron colliders. Possible deviations from the Lorentz symmetry remain poorly constrained in the top quark sector. With a dedicated analysis of $t\bar{t}$ events produced at the LHC, bounds in the top sector can be improved by up to three orders of magnitude relative to Tevatron, the only measurement existing so far. The sensitivity will be even further enhanced at the HL-LHC and future colliders.
Recently the ALICE collaboration has observed an interesting systematic behaviour of ratios of identified particles to pions yields at the LHC, showing that they depend solely on the charged-particle multiplicity in pp, pPb and PbPb collisions. In particular, the yields of (multi)strange particles relative to pions, increases with multiplicity and the enhancement is mode pronounced with increasing strangeness content. We will argue, that such a pattern of arises naturally in the thermal model taking into account exact strangeness conservation. Furthermore, extending the thermal model by includ…
