Hautes Energies
Are the smoking guns of Quark-Gluon Plasma still smoking ? - Enhancement of the strangeness production and suppression of charmonium production in Pb-Pb collisions with ALICE at the LHC
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Europe/Paris
Salle Mondrian
Salle Mondrian
Bat. 25, IPHC
Description
Antonin Maire, Physikalisches Institute, Heidelberg
Note : The slides will be done in English, while the speech may a priori be in French.
Abstract : A part of the research activities led at the Large Hadron Collider (LHC) tackles the studies related to Quark-Gluon Plasma (QGP). This particular state of matter is observed at high energy density and large temperature; under these conditions, nucleons of the usual nuclear structures do not exist anymore and the system is then made of deconfined and thermalized partons.
In the 80's, two signatures were proposed to prove the existence of QGP : the enhancement of the strange quark production and the dissociation of qqbar charm bound states, in the deconfined medium. Experimentally, in heavy-ion collisions (A-A), the enhancement must in particular result in the increased production of strange baryons (Lambda[uds], Xi-[dss], Omega-[sss]), the dissociation, in a reduced production of J/psi[ccbar]. A few decades later, those signatures have now become famous. For any new energy level reachable, any new A-A system available, they are brought to the test of data. More or less successful outcome follow and this way, more or less decisive controversies.
The question of the presentation is the one related to the validity of those signatures at the LHC : what is about the production of strange baryon and charmonia in Pb-Pb collisions at the TeV scale ? Do they keep the promises they were bound to ?
-- I will venture an opinion on those issues. The results obtained so far with the ALICE detector will be presented and discussed together with complementing measurements that are ongoing or foreseen.
Note : The slides will be done in English, while the speech may a priori be in French.
Abstract : A part of the research activities led at the Large Hadron Collider (LHC) tackles the studies related to Quark-Gluon Plasma (QGP). This particular state of matter is observed at high energy density and large temperature; under these conditions, nucleons of the usual nuclear structures do not exist anymore and the system is then made of deconfined and thermalized partons.
In the 80's, two signatures were proposed to prove the existence of QGP : the enhancement of the strange quark production and the dissociation of qqbar charm bound states, in the deconfined medium. Experimentally, in heavy-ion collisions (A-A), the enhancement must in particular result in the increased production of strange baryons (Lambda[uds], Xi-[dss], Omega-[sss]), the dissociation, in a reduced production of J/psi[ccbar]. A few decades later, those signatures have now become famous. For any new energy level reachable, any new A-A system available, they are brought to the test of data. More or less successful outcome follow and this way, more or less decisive controversies.
The question of the presentation is the one related to the validity of those signatures at the LHC : what is about the production of strange baryon and charmonia in Pb-Pb collisions at the TeV scale ? Do they keep the promises they were bound to ?
-- I will venture an opinion on those issues. The results obtained so far with the ALICE detector will be presented and discussed together with complementing measurements that are ongoing or foreseen.