934 research outputs found
Hadronic production of the -wave excited -states ()
Adopting the complete approach of the perturbative QCD (pQCD)
and updated parton distribution functions, we have estimated the hadronic
production of -wave excited -states (). In the estimate,
special care on the relation of the production amplitude to the derivative of
wave function at origin of the potential model is payed. For experimental
references, main uncertainties are discussed, and the total cross sections and
the distributions of the production with reasonable cuts at the energies of
Tevatron and LHC are computed and presented. The results show that -wave
production may contribute to the -meson production indirectly by a factor
about 0.5 of the direct production, and with such a big cross section, it is
worth further to study the possibility to observe the -wave production
itself experimentally.Comment: 23 pages, 9 figures, to replace for revising the misprints ec
The meson annihilation to leptons and inclusive light hadrons
The annihilation of the meson to leptons and inclusive light hadrons is
analyzed in the framework of nonrelativistic QCD (NRQCD) factorization. We find
that the decay mode, which escapes from the helicity suppression, contributes a
sizable fraction width. According to the analysis, the branching ratio due to
the contribution from the color-singlet component of the meson can be of
order (10^{-2}). We also estimate the contributions from the color-octet
components. With the velocity scaling rule of NRQCD, we find that the
color-octet contributions are sizable too, especially, in certain phase space
of the annihilation they are greater than (or comparative to) the color-singlet
component. A few observables relevant to the spectrum of charged lepton are
suggested, that may be used as measurements on the color-octet and
color-singlet components in the future experiments. A typical long
distance contribution in the annihilation is estimated too.Comment: 26 pages, 5 figures (6 eps-files), submitted to Phys. Rev.
Incorporating Radial Flow in the Lattice Gas Model for Nuclear Disassembly
We consider extensions of the lattice gas model to incorporate radial flow.
Experimental data are used to set the magnitude of radial flow. This flow is
then included in the Lattice Gas Model in a microcanonical formalism. For
magnitudes of flow seen in experiments, the main effect of the flow on
observables is a shift along the axis.Comment: Version accepted for publication in Phys. Rev. C, Rapid Communicatio
Anharmonic effects on a phonon number measurement of a quantum mesoscopic mechanical oscillator
We generalize a proposal for detecting single phonon transitions in a single
nanoelectromechanical system (NEMS) to include the intrinsic anharmonicity of
each mechanical oscillator. In this scheme two NEMS oscillators are coupled via
a term quadratic in the amplitude of oscillation for each oscillator. One NEMS
oscillator is driven and strongly damped and becomes a transducer for phonon
number in the other measured oscillator. We derive the conditions for this
measurement scheme to be quantum limited and find a condition on the size of
the anharmonicity. We also derive the relation between the phase diffusion
back-action noise due to number measurement and the localization time for the
measured system to enter a phonon number eigenstate. We relate both these time
scales to the strength of the measured signal, which is an induced current
proportional to the position of the readout oscillator.Comment: 13 pages, 2 figure
A Study of Trait Anhedonia in Non-Clinical Chinese Samples: Evidence from the Chapman Scales for Physical and Social Anhedonia
Background:
Recent studies suggest that anhedonia, an inability to experience pleasure, can be measured as an enduring trait in non-clinical samples. In order to examine trait anhedonia in a non-clinical sample, we examined the properties of a range of widely used questionnaires capturing anhedonia.
Methods:
887 young adults were recruited from colleges. All of them were administered a set of checklists, including Chapman Scale for Social Anhedonia (CRSAS) and the Chapman Scale for Physical Anhedonia Scale (CPAS), The Temporal Experience of Pleasure Scale(TEPS), and The Schizotypal Personality Questionnaire (SPQ).
Results:
Males showed significantly higher level of physical (F = 5.09, p<0.001) and social (F = 4.38, p<0.005) anhedonia than females. As expected, individuals with schizotypal personality features also demonstrated significantly higher scores of physical (t = 3.81, p<0.001) and social (t = 7.33, p<0.001) trait anhedonia than individuals without SPD features, but no difference on self-report anticipatory and consummatory pleasure experience.
Conclusions:
Concerning the comparison on each item of physical and social anhedonia, the results indicated that individuals with SPD feature exhibited higher than individuals without SPD features on more items of social anhedonia than physical anhedonia scale. These preliminary findings suggested that trait anhedonia can be identified a non-clinical sample. Exploring the demographic and clinical correlates of trait anhedonia in the general population may provide clues to the pathogenesis of psychotic disorder.China. Ministry of Science and Technology. National Key Technologies R&D Program (2012BAI36B01)National Science Fund China (Grant no. 81088001)National Science Fund China (Grant no. 91132701)Chinese Academy of Sciences. Knowledge Innovation Project (KSCX2-EW-J-8
Neutrino Oscillations in Supersymmetry without Lepton number conservation and R-parity
With the on-shell renormalization scheme, we discuss neutrino masses up to
one-loop approximation in the Supersymmetry without lepton number conservation
and R-parity. Ii is shown that in this model with experimentally allowed
parameters, and the mixing angles
which are consistent with the present
observation values can be produced. We find that small neutrino mass ( 1
eV) sets a loose constraint on the R-parity violation parameters in the soft
breaking terms.Comment: 22 pages, plus one ps figure, accepted for publication in PR
Thermally-induced expansion in the 8 GeV/c + Au reaction
Fragment kinetic energy spectra for reactions induced by 8.0 GeV/c
beams incident on a Au target have been analyzed in
order to deduce the possible existence and influence of thermal expansion. The
average fragment kinetic energies are observed to increase systematically with
fragment charge but are nearly independent of excitation energy. Comparison of
the data with statistical multifragmentation models indicates the onset of
extra collective thermal expansion near an excitation energy of E*/A
5 MeV. However, this effect is weak relative to the radial
expansion observed in heavy-ion-induced reactions, consistent with the
interpretation that the latter expansion may be driven primarily by dynamical
effects such as compression/decompression.Comment: 12 pages including 4 postscript figure
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