266 Matching Results

Search Results

Advanced search parameters have been applied.

Are the J/psi and chi_c A dependencies the same?

Description: It has been empirically observed that the dependence of J/{psi} and {psi}{prime} production on nuclear mass number A is very similar. This has been postulated to be due to the predominance of color octet pre-resonant states in charmonium production and absorption. Two new experiments, NA60 at CERN and HERA-B at DESY, will measure the {chi}{sub c} A dependence for the first time. These measurements should shed new light on the charmonium production and absorption mechanisms.
Date: September 24, 2001
Creator: Vogt, R.
Partner: UNT Libraries Government Documents Department

The X(3872) boson: Molecule or charmonium

Description: It has been argued that the mystery boson X(3872) is a molecular state consisting of primarily D{sup 0}{bar D}*{sup 0} + {bar D}{sup 0}D*{sup 0}. In contrast, apparent puzzles and potential difficulties have been pointed out for the charmonium assignment of X(3872). They examine several aspects of these alternatives by semi-quantitative methods since quantitatively accurate results are often hard to reach on them. they point out that some of the observed properties of X(3872), in particular, the binding and the production rates are incompatible with the molecule interpretation. Despite puzzles and obstacles, X(3872) may fit more likely to the excited {sup 3}P{sub 1} charmonium than to the molecule after the mixing of c{bar c} with D{bar D}* + {bar D}D* is taken into account.
Date: August 1, 2005
Creator: Suzuki, Mahiko
Partner: UNT Libraries Government Documents Department

Charmonium and charm decays from the Fermilab fixed target program

Description: Recent results on charm decay physics from the Fermilab Fixed Target program will be presented. There have been many physics results within the past year from experiments E687 and E791 and these will be highlighted. Many of these results are related to rare phenomena and searches. These will become even more interesting with the FOCUS experiment dataset of 1 million fully reconstructed charm decays. Preliminary signals from FOCUS as well as from SELEX will be presented together with prospects for the future. Preliminary results from E835 on the {eta}`{sub c} search will also be presented.
Date: May 1, 1998
Creator: Cheung, G.W.K.
Partner: UNT Libraries Government Documents Department

Quarkonium: New Developments

Description: To illustrate the campaign to understand heavy quarkonium systems, the author focuses on a puzzling new state, X(3872) {yields} {pi}{sup +}{pi}{sup -} J/{psi}. Studying the influence of open-charm channels on charmonium properties leads us to propose a new charmonium spectroscopy: additional discrete charmonium levels that can be discovered as narrow resonances of charmed and anticharmed mesons. I recall some expectations for a new spectroscopy of mesons with beauty and charm, the B{sub c} (b{bar c}) system. Throughout, I call attention to open issues for theory and experiment.
Date: March 23, 2004
Creator: Quigg, Chris
Partner: UNT Libraries Government Documents Department

The Lost tribes of charmonium

Description: To illustrate the campaign to extend our knowledge of the charmonium spectrum, the author focuses on a puzzling new state, X(3872) {yields} {pi}{sup +} {pi}{sup -} J/{psi}. Studying the influence of open-charm channels on charmonium properties leads us to propose a new charmonium spectroscopy: additional discrete charmonium levels that can be discovered as narrow resonances of charmed and anticharmed mesons. The author calls attention to open issues for theory and experiment.
Date: July 23, 2004
Creator: Quigg, Chris
Partner: UNT Libraries Government Documents Department

Properties of Exotic Charmonium-like States at CDF

Description: We report the recent evidence for a new narrow structure, Y (4140), decaying to the J/{psi}{phi} final state, in exclusive B{sup +} {yields} J/{psi}{phi}K{sup +} decays in a data sample corresponding to an integrated luminosity of 2.7 fb{sup -1} collected at the CDF II detector. This narrow structure with its mass well above open charm pairs is unlikely to be a candidate for a conventional charmonium state. From a study of the X(3872) mass and width based on the world's largest sample of X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -} decays, we find that our X(3872) signal is consistent with a single state, and leads to the most precise measurement of the X(3872) mass.
Date: June 1, 2009
Creator: Yi, Kai & U., /Iowa
Partner: UNT Libraries Government Documents Department

New states above charm threshold

Description: We revise and extend expectations for the properties of charmonium states that lie above charm threshold, in light of new experimental information. We refine the Cornell coupled-channel model for the coupling of c{bar c} levels to two-meson states, defining resonance masses and widths by pole positions in the complex energy plane, and suggest new targets for experiment.
Date: November 1, 2005
Creator: Eichten, Estia J.; /Fermilab; Lane, Kenneth; U., /Boston; Quigg, Chris & /Fermilab
Partner: UNT Libraries Government Documents Department

Measurements of sin2beta at BaBar with Charmonium and Penguin Decays

Description: This article summarizes measurements of time-dependent CP asymmetries in decays of neutral B mesons to charmonium, open-charm and gluonic penguin-dominated charmless final states. Unless otherwise stated, these measurements are based on a sample of approximately 230 million {Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR detector at the PEP-II asymmetric-energy B-factory.
Date: December 14, 2005
Creator: George, Katherine A. & U., /Liverpool
Partner: UNT Libraries Government Documents Department

Measurements of the CKM Angle Beta/Phi(1) at the B Factories

Description: We report measurements of time-dependent CP asymmetries related to the CKM angle {beta}/{phi}{sub 1}, using decays of neutral B mesons to charmonium, open charm and in b {yields} s loop-dominated processes. A preliminary measurement of time-dependent CP asymmetries in B{sup 0} {yields} {rho}{sup 0}(770)K{sub S}{sup 0} decays from the BABAR experiment is given here.
Date: August 23, 2006
Creator: Ocariz, J. & /Paris U., VI-VII
Partner: UNT Libraries Government Documents Department

Averages of B-Hadron Properties at the End of 2005

Description: This article reports world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results as of at the end of 2005. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries.
Date: September 27, 2006
Creator: Barberio, E.; U., /Melbourne; Bizjak, I.; /Novosibirsk, IYF; Blyth, S.; /CERN et al.
Partner: UNT Libraries Government Documents Department

Pentaquarks and New Hadron Spectroscopy at BaBar

Description: Recent results on the search for pentaquarks and on charmonium spectroscopy at BABAR are reviewed. The latter includes the observation of the puzzling new state X(3872) {yields} J/{psi} {pi}{sup +} {pi}{sup -} in B decays, and the searches for X(3872) in two-body B decays and initial state radiation events.
Date: July 11, 2005
Creator: Ricciardi, S. & /Royal Holloway, U. of London
Partner: UNT Libraries Government Documents Department

Charmonium production in P-A collisions.

Description: A review of J / {psi} and {psi}' production (charmonium) in proton-nucleus collisions is given including results from measurements at fixed target experiments at both Fermilab (E866/NuSea) and CERN (NA50) and some discussion of planned measurements at RHIC and NA60. The important physics that contributes to the large suppression in production of charmonium will be discussed as will be information from complementary measurements of open-charm production, and the Drell-Yan process. The differences in the results from Fermilab and CERN and the evolution of this physics to RHIC energies will be shown. The importance of a clear understanding of these effects in order to use J / {psi} suppression as a tool for study of the Quark-gluon plasma in nucleus-nucleus collisions at RHIC will be highlighted.
Date: January 1, 2001
Creator: Leitch, M. J.
Partner: UNT Libraries Government Documents Department

Study of the Exclusive Initial-State-RadiationProduction of the DDbar System

Description: A search for charmonium and other new states is performed in a study of exclusive initial-state-radiation production of D{bar D} events from electron-positron annihilations at a center-of-mass energy of 10.58 GeV. The data sample corresponds to an integrated luminosity of 384 fb{sup -1} and was recorded by the BABAR experiment at the PEP-II storage ring. The D{bar D} mass spectrum shows clear evidence of the {psi}(3770) plus other structures near 3.9, 4.1, and 4.4 GeV/c2. No evidence for Y (4260) {yields} D{bar D} is observed, leading to an upper limit of {Beta}(Y (4260) {yields} D{bar D})/{Beta}(Y (4260) {yields} J/{psi}{pi}{sup +}{pi}{sup -}) < 1.0 at 90% confidence level.
Date: October 9, 2007
Creator: Collaboration, The BABAR & Aubert, B.
Partner: UNT Libraries Government Documents Department

Update on onium masses with three flavors of dynamical quarks

Description: We update results presented at Lattice 2005 on charmonium masses. New ensembles of gauge configurations with 2+1 flavors of improved staggered quarks have been analyzed. Statistics have been increased for other ensembles. New results are also available for P-wave mesons and for bottomonium on selected ensembles.
Date: January 1, 2006
Creator: Gottlieb, Steven A.; Levkova, L.; U., /Indiana; Di Pierro, Massimo; U., /DePaul; El-Khadra, Aida Xenia et al.
Partner: UNT Libraries Government Documents Department

Charmonium Spectroscopy (X,Y,Z) at the B Factories

Description: Since 2003 several states in the charmonium mass region were discovered. While in the conventional c{bar c} spectrum some states are missing, the number of states observed up to now is larger than empty spaces in the c{bar c} spectrum. This, together with other difficulties to explain observed states as a c{bar c} mesons triggered discussions on a possible exotic interpretations. In this proceedings we present current experimental status from B-factories of the so called X, Y and Z states.
Date: April 3, 2012
Creator: Kreps, Michal & U., /Karlsruhe
Partner: UNT Libraries Government Documents Department

Exclusive Initial-State-Radiation Production of the DDbar,D*Dbar, and D*D*bar Systems

Description: We perform a study of the exclusive production of D{bar D}, D*{bar D}, and D*{bar D}* in initial-state-radiation events, from e{sup +}e{sup -} annihilations at a center-of-mass energy near 10.58 GeV, to search for charmonium and possible new resonances. The data sample corresponds to an integrated luminosity of 384 fb{sup -1} and was recorded by the BABAR experiment at the PEP-II storage rings. The D{bar D}, D*{bar D}, and D*{bar D}* mass spectra show clear evidence of several {psi} resonances. However, there is no evidence for Y(4260) {yields} D*{bar D} or Y(4260) {yields} D*{bar D}*.
Date: June 19, 2009
Creator: Aubert, B.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Absolute Branching Fractions of$B^\pm \to K^\pm X_{c\bar c}$

Description: We study the two-body decays of B{sup {+-}} mesons to K{sup {+-}} and a charmonium state, X{sub c{bar c}}, in a sample of 210.5 fb{sup -1} of data from the BABAR experiment. We perform measurements of absolute branching fractions {Beta}(B{sup {+-}} {yields} K{sup {+-}} X{sub c{bar c}}) using a missing mass technique, and report several new or improved results. In particular, the upper limit {Beta}(B{sup {+-}} {yields} K{sup {+-}}(3872)) < 3.2 x 10{sup -4} at 90% CL and the inferred lower limit {Beta}(X(3872) {yields} J/{psi}{pi}{sup +}{pi}{sup -}) > 4.2% will help in understanding the nature of the recently discovered X(3872).
Date: November 2, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department