Form Factors and Decay Rates for Heavy 'lâmbda' Semileptonic Decays from QCD Sum Rules PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Form Factors and Decay Rates for Heavy 'lâmbda' Semileptonic Decays from QCD Sum Rules PDF full book. Access full book title Form Factors and Decay Rates for Heavy 'lâmbda' Semileptonic Decays from QCD Sum Rules by R. S. Marques de Carvalho. Download full books in PDF and EPUB format.
Author: R. S. Marques de Carvalho
Publisher:
ISBN:
Category :
Languages : en
Pages : 44
Get Book Here
Book Description
Author: R. S. Marques de Carvalho
Publisher:
ISBN:
Category :
Languages : en
Pages : 44
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
The semileptonic decays of [Lambda]{sub c} and [Lambda]{sub b} are treated in the framework of a constituent quark model. Both nonrelativistic and semirelativistic Hamiltonians are used to obtain the baryon wave functions from a fit to the spectra, and the wave functions are expanded in both the harmonic oscillator and Sturmian bases. The latter basis leads to form factors in which the kinematic dependence on q2 is in the form of multipoles, and the resulting form factors fall faster as a function of q2 in the available kinematic ranges. As a result, decay rates obtained in the two models using the Sturmian basis are significantly smaller than those obtained using the harmonic oscillator basis. In the case of the [Lambda]{sub c}, decay rates calculated using the Sturmian basis are closer to the experimentally reported rates. However, we find a semileptonic branching fraction for the [Lambda]{sub c} to decay to excited [Lambda]* states of 11% to 19%, in contradiction with what is assumed in available experimental analyses. Our prediction for the [Lambda]{sub b} semileptonic decays is that decays to the ground state [Lambda]{sub c} provide a little less than 70% of the total semileptonic decay rate. For the decays [Lambda]{sub b} → [Lambda]{sub c}, the analytic form factors we obtain satisfy the relations expected from heavy-quark effective theory at the non-recoil point, at leading and next-to-leading orders in the heavy-quark expansion. In addition, some features of the heavy-quark limit are shown to naturally persist as the mass of the heavy quark in the daughter baryon is decreased.
Author: Lev A. Koyrakh
Publisher:
ISBN:
Category :
Languages : en
Pages : 218
Get Book Here
Book Description
Author: Maximilian Emmerich
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 453
Get Book Here
Book Description
We use the heavy quark effective theory to investigate the form factors that describe the semileptonic decays lambda+c -> lambda e+ nu, to order 1/mc. We find that a total of four form factors are needed to this order, in contrast with two form factors to leading order, and six form factors in the most general case. We point out some relationships that arise among the general form factors.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: S. Aoki
Publisher:
ISBN:
Category :
Languages : en
Pages : 3
Get Book Here
Book Description
Author: V. N. Bajer
Publisher:
ISBN:
Category :
Languages : en
Pages : 16
Get Book Here
Book Description
Author: John Jaros
Publisher: World Scientific
ISBN: 9789810241896
Category : Science
Languages : en
Pages : 952
Get Book Here
Book Description
Stanford University hosted the XIX International Symposium on Lepton and Photon Interactions at High Energies on August 9 - 14, 1999, at the Law School on the Stanford University Campus, the site of the previous Symposia. This volume constitutes the proceedings of the Symposium.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 34
Get Book Here
Book Description
The existing calculations of the form factors describing the decay B2!e? from QCD sum rules have yielded conflicting results at small values of the invariant mass squared of the lepton pair. We demonstrate that the disagreement originates from the failure of the short-distance expansion to describe the? meson distribution amplitude in the region where almost the whole momentum is carried by one of the constituents. This limits the applicability of QCD sum rules based on the short-distance expansion of a three-point correlation function to heavy-to-light transitions and calls for an expansion around the light cone, as realized in the light-cone sum rule approach. We derive and update light-cone sum rules for all the semileptonic form factors, using recent results on the? meson distribution amplitudes. The results are presented in detail together with a careful analysis of the uncertainties, including estimates of higher-twist effects, and compared to lattice calculations and recent CLEO measurements. We also derive a set of?improved? three-point sum rules, in which some of the problems of the short-distance expansion are avoided and whose results agree to good accuracy with those from light-cone sum rules.
