Measurement of χc1(3872) production in proton-proton collisions at $$ \sqrt{s} $$ = 8 and 13 TeV

Abstract

The production cross-section of the χc1(3872) state relative to the ψ(2S) meson is measured using proton-proton collision data collected with the LHCb experiment at centre-of-mass energies of $$ \sqrt{s} $$ s = 8 and 13 TeV, corresponding to integrated luminosities of 2.0 and 5.4 fb−1, respectively. The two mesons are reconstructed in the J/ψπ+π− final state. The ratios of the prompt and nonprompt χc1(3872) to ψ(2S) production cross-sections are measured as a function of transverse momentum, pT, and rapidity, y, of the χc1(3872) and ψ(2S) states, in the kinematic range 4 < pT< 20 GeV/c and 2.0 < y < 4.5. The prompt ratio is found to increase with pT, independently of y. For the prompt component, the double ratio of the χc1(3872) and ψ(2S) production cross-sections between 13 and 8 TeV is observed to be consistent with unity, independent of pT and centre-of-mass energy.

Novel correlated $$ {D}^0{\overline{D}}^0 $$ systems for c/b physics and tests of T/CPT

“…Large cross sections for pp → χ c1 (3872)X have been observed by CMS [146], ATLAS [147], and LHCb [148,149].…”

Chiral perturbation theory for heavy hadrons and chiral effective field theory for heavy hadronic molecules

“…The authors of Ref. [203] argued that the experimental prompt production data of the X(3872) [204,205,206,207,208,209] challenged the hadronic molecule interpretation. The prompt and non-prompt contributions are discriminated by analyzing displacement of the production vertex.…”

“…At O(p 3 ), the tree level contribution to the strong decays stems from the same Lagrangians of the axial vector currents in Eq. (209). The LO results multiplied by the wave function renormalization factors will contribute to the O(p 3 ) strong decay amplitudes.…”

“…40. In fact, a heated topic about the X(3872) is its sub- stantial prompt production [204,205,206,207,208,209], which was often used as an evidence against the molecular interpretation of the X(3872) [203]. In the hadron collider, the X(3872) can be produced from either bottom hadron decays or QCD mechanism.…”

Analytic continuation of the relativistic three-particle scattering amplitudes

“…The majority of QCD states are unstable resonances that reveal themselves in reactions with final products consisting of three and more particles [1][2][3][4]. Among the most notable examples are the lightest excitation of the proton, Roper resonance N * (1440), a hybrid-meson candidate π 1 (1600), the charmed-molecule candidate χ c1 (3872), and its cousin, the recently discovered tetraquark candidate T + cc (3872) [5][6][7][8][9][10][11][12][13][14]. Systematic analysis of these states requires understanding the complicated final state interactions and building robust multi-body reaction amplitudes that satisfy the grounding principles of quantum mechanics, such as unitarity and analyticity.…”