Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Multiplicity dependent production of Xc1_\mathcal{X_{c1}}(3872)

In the last two decades, many hadronic resonances were discovered which are incompatible with the theoretical framework describing conventional mesons and baryons. Among these is the $\chi_{c1}(3872)$, a suspected tetraquark state, first observed in decays of $B$ hadrons into $\rm J/ \psi \pi^+ \pi^-$. The hadronic medium produced in high multiplicity $pp$ collisions allows us to study the onset of nuclear effects on these hadrons, and can thus help us to unveil more about the nature of the $\chi_{c1}(3872)$. The common decay channel with that of a conventional charmonium state $\psi (2\rm S)$ makes the latter an excellent reference for such studies, as we know more about its phenomenology. This talk discusses the recent preliminary results from LHCb on the measurement of the relative suppression of $\chi_{c1}(3872)$ over $\psi (2\rm S)$ exploring their shared $\rm J/ \psi \pi^+ \pi^-$ decay channel in $pp$ collisions at $\sqrt{s} = 8 \text{ TeV}$

Study of the J/ψ\rm{J}/\psi production in pp collisions at s\sqrt{s} = 5.02 TeV and of the J/ψ\rm{J}/\psi production multiplicity dependence in p-Pb collisions at sNN\sqrt{s_{\rm{NN}}} = 8.16 TeV with ALICE at the LHC

The ALICE experiment at CERN probes the state of hot and dense QCD matter created in ultrarelativistic heavy ion collisions - the Quark Gluon Plasma (QGP). Due to its short lifetime, the QGP can be studied only via its signatures. The suppression of $\rm{J}/\psi$ was proposed as a proof of formation of the deconfined medium. Nevertheless, it became clear that the real picture is far more complex as there are other competing mechanisms affecting the $\rm{J}/\psi$ production. To understand which effects acting on the $\rm{J}/\psi$ production in nucleus-nucleus collisions truly stem from the presence of the QGP, ALICE also studies the production of $\rm{J}/\psi$ in pp and p-Pb collisions. The QGP is expected not to form in these systems. Furthermore, measurements of the $\rm{J}/\psi$ production in p-Pb collisions can unveil information on the effects originating from the binding of the nucleons in the nucleus, referred to as the cold nuclear matter effects (CNM). The objective of this thesis is to study the production of $\rm{J}/\psi$ at forward rapidity with the ALICE Muon Spectrometer. The inclusive $\rm{J}/\psi$ production cross section in pp collisions at $\sqrt{s}$ = 5.02 TeV, and its dependence on \pt and rapidity, were examined and compared with theoretical calculations as well as measurement at other LHC energies. The data are well described by a sum of pQCD calculations for prompt and FONLL calculations for non-prompt contribution. The multiplicity differential $\rm{J}/\psi$ production was studied in p-Pb and Pb-p collisions at $\sqrt{s_{\rm{NN}}}$ = 8.16 TeV, as well as its mean transverse momentum. The measurement shows a rapidity dependent behaviour of relative $\rm{J}/\psi$ yields. The $\rm{J}/\psi$ mean transverse momentum on the other hand is identical in the two measured rapidity intervals. The new analysis increased the precision and extended the measurement to higher multiplicities compared to previous measurement at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV. We find that both relative yields and relative \ave{\pt} are independent of centre-of-mass energy

Quarkonia production in pPb collisions at LHCb

We present LHCb results on charmonia production in proton-lead collisions, using the data collected in 2016 at sqrt(s_NN) = 8.16 TeV nucleon-nucleon centre-of-mass energy, in the forward region (pseudorapidity between 2 and 5), covering forward (pPb configuration) and backward (Pbp configuration) rapidities. Measurements include prompt and from-b-decay components which are disentangled. The large increase in size of the data sample, compared to the 5 TeV sample collected in 2013, allows a remarkable improvement in the accuracy of the studies of nuclear matter effects