$\phi$-Meson production at forward rapidity in p-Pb collisions at $\sqrt{S_{NN}}$=5.02 TeV and in pp collisions at $\sqrt{S}$=2.76 TeV

J-L. Charvet (1, 2) , V.J.G. Feuillard (3) , A. Rakotozafindrabe (1, 3) , J. Adam (4, 1) , Laurent Aphecetche , B. Audurier , A. Baldisseri (2, 1) , H. Borel (2, 1) , J. Castillo Castellanos (2, 1) , C. Cheshkov (5) , B. Cheynis (5) , L. Ducroux (5) , Marie Germain , J.-Y. Grossiord (5) , B. Hippolyte , A. Lardeux (3) , A. Maire , L. Massacrier , L. Molnar , D.A. Moreira de Godoy , A. Morreale , H. Pereira da Costa (1, 2) , Philippe Pillot , L. Ronflette , Y. Schutz , Alexandre Shabetai , Diego Stocco , B. Teyssier (5) , R. Tieulent (5) , A. Uras (5) , R. Vernet , M. Wang , G. Conesa Balbastre , J. Faivre , C. Furget , R. Guernane , J.S. Real , C. Silvestre , A. Vauthier , Z. Conesa del Valle (6, 1) , I. Das , B. Espagnon , C. Hadjidakis , I. Lakomov , C. Suire , J.D. Tapia Takaki , M. Tarhini , L. Valencia Palomo , Guillaume Batigne , I. Belikov , Gines Martinez Garcia , J. Martin Blanco

1 Alice Collaboration
2 DPHN - Département de Physique Nucléaire (ex SPhN)
3 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
4 FJFI CTU - Faculty of Nuclear Sciences and Physical Engineering [Prague]
5 IPNL - Institut de Physique Nucléaire de Lyon
6 LLR - Laboratoire Leprince-Ringuet

The first study of $\phi$-meson production in p–Pb collisions at forward and backward rapidity, at a nucleon– nucleon centre-of-mass energy $\sqrt{S_{NN}}$= 5.02 TeV, has been performed with the ALICE apparatus at the LHC. The $\phi$-mesons have been identified in the dimuon decay channel in the transverse momentum ($p_T$) range 1 < $p_T$ < 7 GeV/c, both in the p-going (2.03 < y < 3.53) and the Pb-going (−4.46 < y < −2.96) directions — where $y$ stands for the rapidity in the nucleon–nucleon centre-of-mass — the integrated luminosity amounting to 5.01 ± 0.19 nb$^{−1}$ and 5.81 ± 0.20 nb$^{−1}$ , respectively, for the two data samples. Differential cross sections as a function of transverse momentum and rapidity are presented. The forward–backward ratio for $\phi$-meson production is measured for 2.96 < |y| < 3.53, resulting in a ratio ∼ 0.5 with no significant $p_T$ dependence within the uncertainties. The $p_T$ dependence of the $\phi$ nuclear modification factor R$_{pPb}$ exhibits an enhancement up to a factor 1.6 at $\phi$= 3–4 GeV/c in the Pb-going direction. The $p_T$ dependence of the $\phi$-meson cross section in pp collisions at $\sqrt s$ = 2.76 TeV, which is used to determine a reference for the p–Pb results, is also presented here for 1 < $p_T$ < 5 GeV/c and 2.5 < y < 4, for a 78 ± 3 nb$^{−1}$ integrated luminosity sample.

Mots clés: STRANGENESS; LHC; ALICE; PERSPECTIVE; QUARK-GLUON PLASMA; TRANSVERSE-MOMENTUM DEPENDENCE; ROOT-S-NN=5.02 TEV

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

J-L. Charvet, V.J.G. Feuillard, A. Rakotozafindrabe, J. Adam, Laurent Aphecetche, et al.. $\phi$-Meson production at forward rapidity in p-Pb collisions at $\sqrt{S_{NN}}$=5.02 TeV and in pp collisions at $\sqrt{S}$=2.76 TeV. Physics Letters B, 2017, 768, pp.203-217. ⟨10.1016/j.physletb.2017.01.074⟩. ⟨in2p3-01170083v2⟩