Simultaneous production of charmonium and bottomonium mesons at the LHC

Abstract

Inclusive production of ΥJ/ψ pair in proton-proton interation at LHCb is considered. This process is forbidden at leading order of perturbation theory, so such channels as double parton scattering, χ b χ c pair production with subsequent radiative decays of P -wave quarkonia, contributions of color-octet states, and NLO corrections are studied in details. For all these channels we present theoretical predictions of total cross sections at LHCb and distributions over different kinematical variables.According to presented in the paper results, double parton interaction gives main contribution to the cross section of the considered reaction. PACS numbers: 13.85.-t, 14.40.Pq, 12.39.Jh I. INTRODUCTION Inclusive double production of heavy quarkonia was observed in NA3 experiment, where production of two J/ψ mesons in πN interaction was studied. The cross section of double J/ψ production was suppressed by about three orders of magnitude in comparison with single J/ψ. Such suppression can be easily explained at leading order (LO) of perturbative QCD [1, 2]. In low energy hadronic collisions quark-antiquark subprocess qq → J/ψJ/ψ gives main contribution to the considered reaction, while in the case of high energy interactions gluonic subprocesses gg → J/ψJ/ψ are dominant. Leading order O(α 4 s ) QCD predictions and subsequent next to leading order (NLO) corrections [3] are in good agreement with * Electronic address: Anatolii.Likhoded@ihep.ru † Electronic address: alexey.luchinsky@ihep.ru ‡ Electronic address: stvlpos@mail.ru

RMS and charge radii in a potential model

“…Hopefully, future experiments eg., PANDA [38], LHCb [19] will yield more information to test the validity of the simple relations as well as data.…”

“…(1) cannot be measured with electromagnetic probe. The RMS radius is nearly the average <r 2 > of the quark wave function, which presumably may be determined in Quark Gluon Plasma (QGP) experiments presently studied at LHC [19]. However a simple approximate relationship between the two can be found from the following equation…”

Open charm production in double parton scattering processes in the forward kinematics

“…The important advantage of these processes as compared to the processes experimentally studied before is that in this kinematics the SPS production of D-meson pairs is practically negligible [28][29][30] and the dominant process is the DPS production of cc pairs by gluons, thus permitting to use the methods developed in [5,8,10,11].…”

“…The recent discovery by the LHCb of the double charm DPS production attracted a lot of attention since it expands the study of multiparton dynamics into a new kinematics region of large rapidities [24][25][26][27], and since the background from the leading twist processes is very strongly suppressed in this kinematics [28][29][30].…”

Production of χc pairs with large rapidity separation in kT factorization

“…There has been recently also a calculation for χ c χ b production [24] using collinear gluon distributions. Notice that in the latter case, within the color-singlet model the gluon exchange mechanism is even the exact leading order in this channel.…”