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Exclusive semileptonic decays of heavy mesons provide interesting information on systems consisting of quarks of unequal mass. We express the formfactors of the hadronic current in terms of relativistic bound state wave functions for which we take the solutions of a relativistic harmonic oscillator potential. The wave function overlap is determined by the quark mass dependent longitudinal momentum distribution and differs from results based on non relativistic wave functions. The semileptonic widths and lepton spectra are calculated using in addition nearest pole dominance for the momentum transfer dependence of the formfactors. We compare our results with recent experimental data. The formfactor calculation also allows an estimate of special nonleptonic transitions. From the CLEO results on \(\bar B^0 \to \pi ^ + \pi ^ -\) and \(\bar B^0 \to D^{* + } + \pi ^ -\) we find for the corresponding Kobayashi-Maskawa matrix element ratio the limit |V ub /V cb |?0.3. 相似文献
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Balk S. Körner J. G. Pirjol D. Schilcher K. 《Zeitschrift fur Physik C Particles and Fields》1994,64(1):37-44
Starting from an operator product expansion in the heavy quark effective theory up to order 1/m
b
2
we calculate the inclusive semileptonic decays of unpolarized bottom hadrons including lepton mass effects. We calculate the differential decay spectra d/(dE
), and the total decay rate forB meson decays to final states containing a lepton.Supported by the Graduiertenkolleg Teilchenphysik, Universität Mainz 相似文献
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G. Köpp G. Kramer W. F. Palmer G. A. Schuler 《Zeitschrift fur Physik C Particles and Fields》1990,48(2):327-339
We study the exclusive semileptonicD meson decaysD→K+π+l+ν. For this we develop the general formalism for the joint angular distribution of the charged lepton and theK meson and calculate the helicity dependent decay widths which determine the full angular distribution for several models withK *(892) andK 0 * (1430) intermediate state with nonresonant background terms calculated from chiral Lagrangians. 相似文献
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A.?Kadeer J.?G.?K?rner U.?Moosbrugger 《The European Physical Journal C - Particles and Fields》2009,59(1):27-47
Using the helicity method we derive complete formulas for the joint angular decay distributions occurring in semileptonic
hyperon decays including lepton-mass and polarization effects. Compared to the traditional covariant calculation, the helicity
method allows one to organize the calculation of the angular decay distributions in a very compact and efficient way. In the
helicity method the angular analysis is of cascade type, i.e. each decay in the decay chain is analyzed in the respective
rest system of that particle. Such an approach is ideally suited as input for a Monte Carlo event generation program. As a
specific example we take the decay
(l
−=e
−,μ
−) followed by the nonleptonic decay Σ
+→p+π
0 for which we show a few examples of decay distributions which are generated from a Monte Carlo program based on the formulas
presented in this paper. All the results of this paper are also applicable to the semileptonic and nonleptonic decays of ground-state
charm and bottom baryons, and to the decays of the top quark. 相似文献
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Harpreet Kaur 《Pramana》1999,52(4):389-393
The beauty-conserving strangeness-changing decays ofB
s meson are examined. In the charm sector, charm-conserving strangeness changing (Δc = 0, Δs ≠ 0) decays are Cabibbo suppressed and are governed by the CKM elementV
us which is much smaller than the CKM diagonal elementV
cs, so may be of little interest. On the other hand, in theb-sector, beauty-conserving strangeness changing (Δb = 0, Δs ≠ 0) decays are CKM allowed as the CKM matrix elementV
us governing such decays is much larger thanV
bc orV
bu which govern respectively theb →c orb →u transitions. The phase space available, however, is too small for the decays considered here. The numerical estimates for
the decay widths of two such modes ofB
s meson are presented. 相似文献
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Rudolph Tegen 《Zeitschrift fur Physik C Particles and Fields》1981,11(2):165-168
The semileptonic three particle decays of the tau provide determinations of the tau neutrino mass. The shift of the maximal energy of the observable final state particles islinear in the neutrino mass. The endpoint energy of the pion and a partially integrated decay rate in τ → πωv τ and τ → πρV τ are sensitive to a neutrino mass smaller than 100 MeV. Thus, the present bound on \(m_{v_\tau } \) can significantly be improved. 相似文献
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Fulton R Jensen T Johnson DR Kagan H Kass R Morrow F Whitmore J Wilson P Bortoletto D Chen W Dominick J McIlwain RL Miller DH Ng CR Schaffner SF Shibata EI Shipsey IP Yao W Battle M Sparks K Thorndike EH Wang C Alam MS Kim IJ Li WC Romero V Sun CR Wang P Zoeller MM Goldberg M Haupt T Horwitz N Jain V Mestayer MD Moneti GC Rozen Y Rubin P Sharma V Skwarnicki T Thulasidas M Zhu G Csorna SE Letson T Alexander J Artuso M Bebek C Berkelman K Browder T Cassel DG Cheu E Coffman DM Crawford G DeWire JW 《Physical review D: Particles and fields》1991,43(3):651-663
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Considering the constraints from the experimental data on μ→eγ, μ→3e, μ–e conversion, etc., we analyze the lepton flavor violating decays ?(J/Ψ,?(1S))→e+μ−(μ+τ−) in the scenarios of the minimal supersymmetric extensions of Standard Model with seesaw mechanism. Numerically, there is parameter space that the LFV processes of J/Ψ(?)→μ+τ− can reach the upper experimental bounds, meanwhile the theoretical predictions on μ→eγ, μ→3e, μ–e conversion satisfy the present experimental bounds. For searching of new physics, lepton flavor violating processes J/Ψ(?)→μ+τ− may be more promising and effective channels. 相似文献