Ground and excited state charmonium production in p + p collisions at s = 200 GeV
Not Available
Adare, A.↗
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Results for “CHARMONIUM”
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Search for charmonium and charmoniumlike states in Υ ( 2 S ) radiative decays
Using a sample of 158 x 10⁶ Υ(2S) events collected with the Belle detector, charmonium and charmoniumlike states with even charge parity are searched for in Υ(2S) radiative decays. No significant Xcl or nc signal is observed, and the following upper limits at 90% confidence level (C. L.) are obtained: Β(Υ(2S)→YXco)<1.0×10 - ⁴, Β(Υ(2S)→yxc1)<3.6×10 - ⁶, Β(Υ(2S)→yxc2)<1.5 x 10 - ⁵, and Β(Υ(2S)→ync)<2.7×10 - ⁵. No significant signal of any charmoniumlike state is observed, and we obtain the limits Β(Υ(2S)→yX(3872)) x Β(X(3872)→π⁺π⁻J/ψ)<0.8×10-6, Β(Υ(2S)→γX(3872))× Β(X(3872)→ π⁺π⁻π⁰Jlψ)<2.4 x 10⁻⁶, Β(Υ(2S)→γX(3915))× Β(X(3915)→ωJ/ψ)<2.8×10⁻⁶, Β(Υ(2S)→γY(4140)) x Β(Y(4140)→$\phi$J/ψ))<1.2 x 10 - ⁶, and Β(Υ(2S)→yX(4350))× Β(X(4350)→$\phi$J/ψ))<1.3×10⁻⁶ at 90% C. L.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Search for double charmonium decays of the P -wave spin-triplet bottomonium states
Not Available
Shen, C. P.↗
Evidence of Υ ( 1 S ) → J / ψ + χ c 1 and search for double-charmonium production in Υ ( 1 S ) and Υ ( 2 S ) decays
Using data samples of 102 × 10 6 Υ ( 1 S ) and 158 × 10 6 Υ ( 2 S ) events collected with the Belle detector, a first experimental search has been made for double-charmonium production in the exclusive decays Υ ( 1 S , 2 S ) → J / ψ ( ψ ' ) + X , where X = η c , χ c J ( J = 0 , 1 , 2 ) , η c ( 2 S ) , X ( 3940 ) , and X ( 4160 ) . No significant signal is observed in the spectra of the mass recoiling against the reconstructed J / ψ or ψ ' except for the evidence of χ c 1 production with a significance of 4.6 σ for Υ ( 1 S ) → J / ψ + χ c 1 . The measured branching fraction B ( Υ ( 1 S ) → J / ψ + χ c 1 ) is [ 3.90 ± 1.21 ( stat ) ± 0.23 ( syst ) ] × 10 - 6 . The 90% C.L. upper limits on the branching fractions of the other modes having a significance of less than 3 σ are determined. In conclusion, these results are consistent with theoretical calculations using the nonrelativistic QCD factorization approach.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Exclusive processes of charmonium production and charmonium wave functions
Results obtained by studying the properties of the leading-twist wave functions for the S- and P-wave states of charmonia are presented. Wave-function models that can be used to calculate various processes involving the production of these mesons were constructed on the basis of these investigations. Calculations for some exclusive processes of charmonium production were performed within the models in question.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Study of charmonium and charmonium-like contributions in $\mathrm{B}^+$ → $\mathrm{J/ψηK^+}$ decays
A study of B+ → J/ψηK + decays, followed by J/ψ → μ + μ – and η → γγ, is performed using a dataset collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb –1 The J/ψη mass spectrum is investigated for contributions from charmonia and charmonium-like states. Evidence is found for the B + →(ψ2(3823) → J/ψη)K + and B + → (ψ(4040) → J/ψη)K + decays with significance of 3.4 and 4.7 standard deviations, respectively. This constitutes the first evidence for the ψ 2 (3823) → J/ψη decay.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Physics with charmonium - Highlights of BESIII and PANDA
The physics of the strong interaction is undoubtedly one of the most challenging areas of modern science. Quantum ChromoDynamics (QCD) is reproducing successfully the physics phenomena at distances much shorter than the size of the nucleon, where perturbation theory can be used yielding results of high precision and predictive power. At larger distance scales, however, perturbative methods cannot be applied anymore, although spectacular phenomena, such as the generation of hadron masses and quark confinement, occur. Studies using charmed quarks and gluon-rich matter have the potential to connect the perturbative and the non-perturbative QCD region. The annihilation of matter with antimatter in the mass regime of charmonium is an ideal environment to discover new states or transitions that could reveal the secrets of the strong interaction. Hadronic and electromagnetic transitions between charmonium states and their decays have been measured with a world-record in precision with the BESIII spectrometer at the electron-positron collider at IHEP Beijing, China. Moreover, unconventional narrow charmonium-rich states have been discovered recently in an energy regime above the open-charm threshold, thereby, possibly initiating a new era in charmonium spectroscopy. The near future experiment, PANDA, at the research facility FAIR in Germany, Darmstadt, will exploit the annihilation of cooled anti-protons with protons to perform charmonium spectroscopy with an incredible precision. I will present the most promising results that have been recently obtained with BESIII together with the future perspectives of PANDA in the field of charmonium spectroscopy.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Color halo scenario of charmonium-like hybrids
The internal structures of J PC =1 -- ,(o,1,2) -+ charmonium-like hybrids are investigated under lattice QCD in the quenched approximation. We define the Bethe-Salpeter wave function (Φn(r)) in the Coulomb gauge as the matrix element of a spatially extended hybrid-like operator ($\bar{c}cg$) between the vacuum and n-th state for J PC , with r being the spatial separation between a localized $\bar{c}c$ component and the chromomagnetic strength tensor. These wave functions exhibit some similarities for states with the aforementioned different quantum numbers, and their r-behaviors (no node for the ground states and one node for the first excited states) imply that r can be a meaningful dynamical variable for these states. Additionally, the mass splittings of the ground states and first excited states of charmonium-like hybrids in these channels are obtained for the first time to be approximately 1.2-1.4 GeV. These results do not support the flux-tube description of heavy-quarkonium-like hybrids in the Born-Oppenheimer approximation. In contrast, a charmonium-like hybrid can be viewed as a "color halo" charmonium for which a relatively localized color octet $\bar{c}c$ is surrounded by gluonic degrees of freedom, which can readily decay into a charmonium state along with one or more light hadrons. The color halo picture is compatible with the decay properties of Y (42600) and suggests LHCb and BelleII to search for (0,1,2) -+ charmonium-like hybrids in Xc0,1,2N and J/ψω(φ) final states.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
The charmonium dissociation in an ''anomalous wind''
We study the charmonium dissociation in a strongly coupled chiral plasma in the presence of magnetic field and axial charge imbalance. This type of plasma carries "anomalous flow" induced by the chiral anomaly and exhibits novel transport phenomena such as chiral magnetic effect. We found that the "anomalous flow" would modify the charmonium color screening length by using the gauge/gravity correspondence. We derive an analytical expression quantifying the "anomalous flow" experienced by a charmonium for a large class of chiral plasma with a gravity dual. We elaborate on the similarity and it qualitative difference between anomalous effects on the charmonium color screening length which are model-dependent and those on the heavy quark drag force which are fixed by the second law of thermodynamics. As a result, we speculate on the possible charmonium dissociation induced by the chiral anomaly in heavy ion collisions.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Measurement of Charmonium Production in $p + p$ and $p + d$ Interactions in the Fermilab SeaQuest Experiment
The Fermilab SeaQuest experiment has measured dimuon events from the interactions of 120GeV proton beam on liquid hydrogen and deuterium targets with dimuon mass between 2 and 9GeV. These dimuon events contain both the Drell-Yan process and the charmonium ($J/\psi$ and $\psi^\prime$) production. Unlike the Drell-Yan process which probes the antiquark distributions in the nucleons, the charmonium production is sensitive to both quark and gluon distributions. SeaQuest has extracted the $\sigma^{pd}/2\sigma^{pp}$ ratio as well as the differential cross sections for charmonium production in the kinematic region of $0.4 < x_F < 0.9$. The $\sigma^{pd}/2\sigma^{pp}$ ratio for charmonium production are found to be significantly different from that of the Drell-Yan process. The measured differential cross sections for charmonium production are compared with theoretical calculations using Color Evaporation Model and Non-Relativistic QCD model.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Potential description of the charmonium from lattice QCD
We present spin-independent and spin-spin interquark potentials for charmonium states, that are calculated using a relativistic heavy quark action for charm quarks on the PACS-CS gauge configurations generated with the Iwasaki gauge action and 2+1 flavors of Wilson clover quark. The interquark potential with finite quark masses is defined through the equal-time Bethe-Salpeter amplitude. The light and strange quark masses are close to the physical point where the pion mass corresponds to M{sub π} ≈ 156(7) MeV, and charm quark mass is tuned to reproduce the experimental values of η{sub c} and J/ψ states. Our simulations are performed with a lattice cutoff of a{sup −1} ≈ 2.2 GeV and a spatial volume of (3 fm){sup 3}. We solve the nonrelativistic Schrödinger equation with resulting charmonium potentials as theoretical inputs. The resultant charmonium spectrum below the open charm threshold shows a fairly good agreement with experimental data of well-established charmonium states.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗