3,936 research outputs found
Semileptonic decays of meson to S-wave charmonium states in the perturbative QCD approach
Inspired by the recent measurement of the ratio of branching fractions
to and final states at the LHCb
detector, we study the semileptonic decays of meson to the S-wave ground
and radially excited 2S and 3S charmonium states with the perturbative QCD
approach. After evaluating the form factors for the transitions , where and denote pseudoscalar and vector S-wave charmonia,
respectively, we calculate the branching ratios for all these semileptonic
decays. The theoretical uncertainty of hadronic input parameters are reduced by
utilizing the light-cone wave function for meson. It is found that the
predicted branching ratios range from up to and could be
measured by the future LHCb experiment. Our prediction for the ratio of
branching fractions is in good
agreement with the data. For decays, the relative
contributions of the longitudinal and transverse polarization are discussed in
different momentum transfer squared regions. These predictions will be tested
on the ongoing and forthcoming experiments.Comment: 12 pages, 3 figures, 5 table
Direct CP violation in
We study the direct CP violation in the decay process in the
Standard Model. An interesting mechanism involving the charge symmetry
violating mixing between and is applied to enlarge the CP
asymmetry. With this mechanism, the maximum differential and localized
integrated CP asymmetries can reach and
, respectively, which still leave plenty room
for CP-violating New Physics to be discovered through this process
Improving thermoelectric properties of p-type Bi2Te3-based alloys by spark plasma sintering
AbstractHigh-performance (Bi2Te3)x(Sb2Te3)1−x bulk materials were prepared by combining fusion technique with spark plasma sintering, and their thermoelectric properties were investigated. The electrical resistivity and Seebeck coefficient increase greatly and the thermal conductivity decreases significantly with the increase of Bi2Te3 content, which leads to a great improvement in the thermoelectric figure of merit ZT. The maximum ZT value reaches 1.33 at 398 K for the composition of 20%Bi2Te3-80%Sb2Te3 with 3% (mass fraction) excess Te
Physical and Mechanical Properties of Herrnholz Granite: An Ideal Experimental Material
Granite, as the most common plutonic rock of the Earth’s crust and the most widely used paving block and building stone in industrial activities, has been widely employed in experimental investigations on its chemical composition, physical properties, and mechanical responses. This chapter focuses on the physical and mechanical properties of Herrnholz granite while emphasizing that it is an ideal experimental material for its homogeneity and fine-grained nature. Among the properties discussed here are density, porosity, pore size distribution, ultrasonic wave velocities, strength, fracture toughness, and hydroscopic/hygroscopic properties. Preliminary laboratory data sets to reveal relationships between the hygroscopic properties and mesoporous character of the Herrnholz granite as a result of water adsorption on internal fabric elements, such as pores, and microcracks
Effects of lifestyle intervention using patient-centered cognitive behavioral therapy among patients with cardio-metabolic syndrome: a randomized, controlled trial
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