Hadrinoc production of χ c -nesons at LHC

Abstract

Hadronic production of P -wave charmonium states χ cJ in hadronic interaction is considered. Using experimental results of CDF and LHCb collaborations we show, that contributions of color-singlet components are dominant. As for color-octet mechanism, we show, that contributions from P -wave states can also be observed, while S-wave states can be neglected. The best experimental observables that give information about relative importance of color-singlet and color-octet components are the ratios χ c2 /χ c1 and χ c0 /χ c1 .

Study of $$\upchi _{{\mathrm {b}}}$$ χ b meson production in $$\mathrm {p} $$ p $$\mathrm {p} $$ p collisions at $$\sqrt{s}=7$$ s = 7 and $$8{\mathrm {\,TeV}} $$ 8 TeV a

“…The yield fractions Nχ b2 /Nχ b1 of the tensor and vector states in each χ b (mP) multiplet are assumed to be equal to 0.5 according to expectations from Refs. [11,47]. For the χ b (1P) and χ b (2P) cases, this choice agrees with direct measurements of the relative productions of χ b2 (1P)/ χ b1 (1P) and χ b2 (2P)/ χ b1 (2P) [22,49].…”

“…These limits are obtained by following the prescription of Ref. [11], where the experimentally measured cross-section ratio of χ c mesons is rescaled to predict the corresponding ratio for χ b mesons. The ratio of cross-sections is then converted to a ratio of yields by taking into account the χ b1 and χ b2 radiative branching fractions and reconstruction efficiencies.…”

“…This contribution could significantly influence the interpretation of the measured polarization of S-wave vector quarkonia. In addition, measurements of the relative production rates of P-wave to S-wave quarkonia, as well as the tensor-to-vector ratios, provide valuable information on colour-octet matrix elements [10][11][12].…”

“…This contribution could significantly influence the interpretation of the measured polarization of S-wave vector quarkonia. In addition, measurements of the relative production rates of P-wave to S-wave quarkonia, as well as the tensor-to-vector ratios, provide valuable information on colour-octet matrix elements [10][11][12].The production of P-wave charmonia, jointly referred to as χ c states, has been studied by the CDF [13] [23,24] experiments.This paper presents a measurement of the fractions of ϒ mesons originating from radiative decays of χ b mesons. Depending on the relative orientation of the quark spins, the χ b states can be either scalar, vector or tensor mesons, denoted by χ bJ with total angular momentum J = 0, 1, 2.…”

Hadronic production of heavy quarkonia at LHC

“…These two states have significantly different p T -behavior and can be well separated by analyzing the available experimental data. As it was shown in our previous works [4,5], the available experimental data can not be explained well by considering only these two states, so contribution from higher octet states should also be considered. In the present paper we perform a rigorous fit of available experimental data including new LHC results and determine both central values and uncertanties for nonpeturbative model parameters.…”