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Title: Inclusive production of the X(3872)

Abstract

If the X(3872) is a loosely-bound D*{sup 0}D{sup 0}/D{sup 0}D*{sup 0} molecule, its inclusive production rate can be described by the NRQCD factorization formalism that applies to inclusive quarkonium production. We argue that if the molecule has quantum numbers J{sup PC}=1{sup ++}, the most important term in the factorization formula should be the color-octet {sup 3}S{sub 1} term. This is also one of the two most important terms in the factorization formulas for {chi}{sub cJ}. Since the color-octet {sup 3}S{sub 1} term dominates {chi}{sub cJ} production for many processes, the ratio of the inclusive direct production rates for X and {chi}{sub cJ} should be roughly the same for these processes. The assumption that the ratio of the production rates for X and {chi}{sub cJ} is the same for all processes is used to estimate the inclusive production rate of X in B meson decays, Z{sup 0} decays, and in pp collisions.

Authors:
 [1]
  1. Physics Department, Ohio State University, Columbus, Ohio 43210 (United States)
Publication Date:
OSTI Identifier:
20774566
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevD.73.011501; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; B MESONS; COLOR MODEL; D MESONS; D*-2010 MESONS; FACTORIZATION; HADRONIC PARTICLE DECAY; INCLUSIVE INTERACTIONS; MESIC MOLECULES; PARITY; PARTICLE PRODUCTION; PROTON-PROTON INTERACTIONS; QUANTUM CHROMODYNAMICS; QUANTUM NUMBERS; QUARKONIUM; SPIN; Z NEUTRAL BOSONS

Citation Formats

Braaten, Eric. Inclusive production of the X(3872). United States: N. p., 2006. Web. doi:10.1103/PhysRevD.73.011501.
Braaten, Eric. Inclusive production of the X(3872). United States. doi:10.1103/PhysRevD.73.011501.
Braaten, Eric. Sun . "Inclusive production of the X(3872)". United States. doi:10.1103/PhysRevD.73.011501.
@article{osti_20774566,
title = {Inclusive production of the X(3872)},
author = {Braaten, Eric},
abstractNote = {If the X(3872) is a loosely-bound D*{sup 0}D{sup 0}/D{sup 0}D*{sup 0} molecule, its inclusive production rate can be described by the NRQCD factorization formalism that applies to inclusive quarkonium production. We argue that if the molecule has quantum numbers J{sup PC}=1{sup ++}, the most important term in the factorization formula should be the color-octet {sup 3}S{sub 1} term. This is also one of the two most important terms in the factorization formulas for {chi}{sub cJ}. Since the color-octet {sup 3}S{sub 1} term dominates {chi}{sub cJ} production for many processes, the ratio of the inclusive direct production rates for X and {chi}{sub cJ} should be roughly the same for these processes. The assumption that the ratio of the production rates for X and {chi}{sub cJ} is the same for all processes is used to estimate the inclusive production rate of X in B meson decays, Z{sup 0} decays, and in pp collisions.},
doi = {10.1103/PhysRevD.73.011501},
journal = {Physical Review. D, Particles Fields},
number = 1,
volume = 73,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • The production of the X(3872) is studied in pp collisions at sqrt(s) = 7 TeV, using decays to J/psi pi pi, where the J/psi decays to two muons. The data were recorded by the CMS experiment and correspond to an integrated luminosity of 4.8 inverse femtobarns. The measurements are performed in a kinematic range in which the X(3872) candidates have a transverse momentum 10 < pt < 50 GeV and rapidity abs(y) < 1.2. The ratio of the X(3872) and psi(2S) cross sections times their branching fractions into J/psi pi pi is measured as a function of pt. In addition,more » the fraction of X(3872) originating from B decays is determined. From these measurements the prompt X(3872) differential cross section times branching fraction as a function of pt is extracted. The pi pi mass spectrum of the J/psi pi pi system in the X(3872) decays is also investigated.« less
  • If the recently discovered charmoniumlike state X(3872) is a loosely bound S-wave molecule of the charm mesons D{sup 0}D*{sup 0} or D*{sup 0}D{sup 0}, it can be produced through the weak decay of the B meson into D{sup 0}D*{sup 0}K or D*{sup 0}D{sup 0}K followed by the coalescence of the charm mesons at a long-distance scale set by the scattering length of the charm mesons. The long-distance factors in the amplitude for the decay B{yields}XK are determined by the binding energy of X, while the short-distance factors are essentially determined by the amplitudes for B{yields}D{sup 0}D*{sup 0}K and B{yields}D*{sup 0}D{supmore » 0}K near the thresholds for the charm mesons. We obtain a crude determination of the short-distance amplitudes by analyzing data from the BABAR Collaboration on the branching fractions for B{yields}D{sup (}*{sup )}D{sup (}*{sup )}K using a factorization assumption, heavy-quark symmetry, and isospin symmetry. The resulting order-of-magnitude estimate of the branching fraction for B{sup +}{yields}XK{sup +} is compatible with observations provided that J/{psi}{pi}{sup +}{pi}{sup -} is a major decay mode of the X. The branching fraction for B{sup 0}{yields}XK{sup 0} is predicted to be suppressed by more than an order of magnitude compared to that for B{sup +}{yields}XK{sup +}.« less
  • The production and decay of the X(3872) are analyzed under the assumption that the X is a weakly bound molecule of the charm mesons D{sup 0}D*{sup 0} and D*{sup 0}D{sup 0}. The decays imply that the large D{sup 0}D*{sup 0} scattering length has an imaginary part. An effective field theory for particles with a large complex scattering length is used to derive factorization formulas for production rates and decay rates of X. If a partial width is calculated in a model with a particular value of the binding energy, the factorization formula can be used to extrapolate to other valuesmore » of the binding energy and to take into account the width of the X. The factorization formulas relate the rates for production of X to those for production of D{sup 0}D*{sup 0} and D*{sup 0}D{sup 0} near threshold. They also imply that the line shape of X differs significantly from that of a Breit-Wigner resonance.« less
  • The X(3872) seems to be a weakly bound hadronic molecule whose constituents are two charm mesons. Its binding energy is much smaller than all the other energy scales in QCD. This separation of scales can be exploited through factorization formulas for production and decay rates of the X. In a low-energy effective field theory for the constituents of the X, the factorization formulas can be derived using the operator product expansion. The derivations are carried out explicitly for the simplest effective theory in which the constituents interact through a contact interaction that produces a large scattering length. The long-distance factorsmore » in the operator product expansions for various observables are calculated nonperturbatively in the interaction strength of the contact interaction. After renormalization of the coupling constant, all remaining ultraviolet divergences can be absorbed into the short-distance factors in the operator product expansions.« less
  • We have searched for prompt production of {chi}{sub c1}, {chi}{sub c2} and X(3872) in continuum e{sup +}e{sup -} annihilations using a 386 fb{sup -1} data sample collected around {radical}(s)=10.6 GeV with the BABAR detector using the {gamma}J/{psi} decay mode. After accounting for the feed-down from {psi}(2S){yields}{gamma}{chi}{sub c1,2}, no significant signal for prompt {chi}{sub c1,2} production is observed. We present improved upper limits at 90% confidence level on the production cross sections of 77 fb for {chi}{sub c1} and 79 fb for {chi}{sub c2}, for events where the {chi}{sub c} momentum exceeds 2.0 GeV and there are at least three additionalmore » charged tracks. These limits are consistent with NRQCD predictions. We also set an upper limit on the prompt production of X(3872) through the decay X(3872){yields}{gamma}J/{psi}.« less