We report measurements of partial branching fractions of inclusive charmless semileptonic B-meson decays at the endpoint of the electron momentum spectrum. The measurements are made in six overlapping momentum intervals that have lower bounds ranging from 1.9 to 2.4 GeV/c and a common upper bound of 2.6 GeV/c, as measured in the centre of mass frame. The results are based on a sample of 29 million BB̄ pairs, accumulated by the Belle detector at the KEKB asymmetric e+e- collider operating on the Υ(4S) resonance. In the momentum interval ranging from 1.9 to 2.6 GeV/c we measure the partial branching fraction ΔB(B→Xueνe)=(8.47±0.37±1.53)×10-4, where the first error is statistical and the second is systematic. A prediction of the partial rate R=(21.69±3.62-1.98+2.18)|Vub|2 ps-1 in this momentum interval based on theory is calculated with input HQET parameters that have been derived from Belle's measurement of the B→Xsγ photon energy spectrum, where the first error is due to the uncertainty on HQET parameters and the second error is from theory. Using both ΔB(B→Xueνe) and R we find |V ub|=(5.08±0.47±0.42-0.23+0.26)×10-3, where the first error is from the partial branching fraction, and the second and third errors are from uncertainties in R.
|Number of pages||13|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Publication status||Published - 2005 Aug 11|
Bibliographical noteFunding Information:
We are grateful to Matthias Neubert, Bjorn Lange, Gil Paz and Stefan Bosch for very helpful discussions, correspondences, explanations and for providing us with their theoretical computations implemented in an inclusive generator. We thank the KEKB group for the excellent operation of the accelerator, the KEK cryogenics group for the efficient operation of the solenoid, and the KEK computer group and the National Institute of Informatics for valuable computing and Super-SINET network support. We acknowledge support from the Ministry of Education, Culture, Sports, Science, and Technology of Japan and the Japan Society for the Promotion of Science; the Australian Research Council, the Australian Department of Education, Science and Training, Australian Postgraduate Award and the David Hay Postgraduate Writing-Up Award; the National Science Foundation of China under contract No. 10175071; the Department of Science and Technology of India; the BK21 program of the Ministry of Education of Korea and the CHEP SRC program of the Korea Science and Engineering Foundation; the Polish State Committee for Scientific Research under contract No. 2P03B 01324; the Ministry of Science and Technology of the Russian Federation; the Ministry of Higher Education, Science and Technology of the Republic of Slovenia; the Swiss National Science Foundation; the National Science Council and the Ministry of Education of Taiwan; and the US Department of Energy.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics