Precision Measurement of the X(3872) Mass in J/ psi pi + pi - Decays

• Main Authors: Xie, Si (Contributor), Makhoul, K. (Contributor), Knuteson, Bruce O. (Contributor), Henderson, C. (Contributor), Hahn, Kristian Allan (Contributor), Goncharov, M. (Contributor), Gomez-Ceballos, Guillelmo (Contributor), Choudalakis, Georgios (Contributor), Bauer, Gerry P. (Contributor), Paus, Christoph M. E. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Physics (Contributor), Massachusetts Institute of Technology. Laboratory for Nuclear Science (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2010-03-02T19:15:34Z.
• Subjects: Article
• Online Access: Get fulltext

We present an analysis of the mass of the X(3872) reconstructed via its decay to J/ψπ[superscript +]π[superscript -] using 2.4  fb[superscript -1] of integrated luminosity from pp̅ collisions at √s=1.96  TeV, collected with the CDF II detector at the Fermilab Tevatron. The possible existence of two nearby mass states is investigated. Within the limits of our experimental resolution the data are consistent with a single state, and having no evidence for two states we set upper limits on the mass difference between two hypothetical states for different assumed ratios of contributions to the observed peak. For equal contributions, the 95% confidence level upper limit on the mass difference is 3.6  MeV/c[superscript 2]. Under the single-state model the X(3872) mass is measured to be 3871.61±0.16(stat)±0.19(syst)  MeV/c[superscript 2], which is the most precise determination to date.
Academy of Finland
Slovak R&D Agency
Programa Consolider-Ingenio 2010, Spain
Ministerio de Ciencia e Innovación, Spain
Russian Foundation for Basic Research
Institut National de Physique Nucleaire et Physique des Particules/CNRS
Royal Society, United Kingdom
Science and Technology Facilities Council, United Kingdom
Korean Research Foundation
Korean Science and Engineering Foundation
Bundesministerium für Bildung und Forschung, Germany
Alfred P. Sloan Foundation
Swiss National Science Foundation
National Science Council of the Republic of China
Natural Sciences and Engineering Research Council of Canada
Ministry of Education, Culture, Sports, Science and Technology of Japan
Italian Istituto Nazionale di Fisica Nucleare
National Science Foundation
United States Department of Energy