We have measured the ratio of prompt production rates of the charmonium states chi(c1) and chi(c2) in 110 pb(-1) of pp collisions at sqrt[s] = 1.8 TeV. The photon from their decay into J/psi(gamma) is reconstructed through conversion into e+e- pairs. The energy resolution this technique provides makes the resolution of the two states possible. We find the ratio of production cross sections sigma(chi(c2))/sigma(chi(c1)) = 0.96+/-0.27(stat)+/-0.11(syst) for events with pT(J/psi) > 4.0 GeV/c, /eta(J/psi)/ < 0.6, and pT(gamma) > 1.0 GeV/c.
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http://dx.doi.org/10.1103/PhysRevLett.86.3963 | DOI Listing |
J Biomech
March 2024
Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China. Electronic address:
To maintain the physiological dynamics of the mitral annulus, mitral annuloplasty rings (MAR) must be flexible. Enhanced flexibility implies decreased resistance to fatigue and potential for fatigue fracture. This study established new methods to test the flexible fatigue life of MAR in-vitro using numerical analysis; the purpose is that the fatigue test could reflect the real stress distribution in-vivo.
View Article and Find Full Text PDFEur Phys J C Part Fields
March 2018
2CERN, Geneva, Switzerland.
A global analysis of ATLAS and CMS measurements reveals that, at mid-rapidity, the directly-produced , and J/ mesons have differential cross sections of seemingly identical shapes, when presented as a function of the mass-rescaled transverse momentum, . This identity of kinematic behaviours among S- and P-wave quarkonia is certainly not a natural expectation of non-relativistic QCD (NRQCD), where each quarkonium state is supposed to reflect a specific family of elementary production processes, of significantly different -differential cross sections. Remarkably, accurate kinematic cancellations among the various NRQCD terms (colour singlets and octets) of its factorization expansion can lead to a surprisingly good description of the data.
View Article and Find Full Text PDFEur Phys J C Part Fields
September 2017
15Sezione INFN di Bologna, Bologna, Italy.
Phys Rev Lett
May 2014
School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China and Collaborative Innovation Center of Quantum Matter, Beijing 100871, China and Center for High Energy Physics, Peking University, Beijing 100871, China.
Prompt χc production at hadron colliders may provide a unique test for the color-octet mechanism in nonrelativistic QCD. We present an analysis for the polarization observables of χc1 and χc2 at next-to-leading order in αS and propose to measure them at the LHC, which is expected to be important for testing the validity of nonrelativistic QCD.
View Article and Find Full Text PDFEur Phys J C Part Fields
December 2012
University of Wisconsin, Madison, USA.
A measurement is presented of the relative prompt production rate of and with 4.6 fb of data collected by the CMS experiment at the LHC in pp collisions at [Formula: see text]. The two states are measured via their radiative decays →J/+, with the photon converting into an ee pair for J/ rapidity |(J/)|<1.
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