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Title: Search for B{sup 0}{yields}pp, {lambda}{lambda} and B{sup +}{yields}p{lambda} at Belle

Abstract

We report on a new search for two-body baryonic decays of the B meson. Improved sensitivity compared to previous Belle results is obtained from 414 fb{sup -1} of data that corresponds to 449x10{sup 6} BB pairs, which were taken on the {upsilon}(4S) resonance and collected with the Belle detector at the KEKB e{sup +}e{sup -} collider. No significant signals are observed and we set the 90% confidence level upper limits: B(B{sup 0}{yields}pp)<1.1x10{sup -7}, B(B{sup 0}{yields}{lambda}{lambda})<3.2x10{sup -7}, and B(B{sup +}{yields}p{lambda})<3.2x10{sup -7}.

Authors:
; ; ; ; ; ; ; ;  [1]; ; ; ; ; ; ; ; ; ; ;  [2]
  1. Department of Physics, National Taiwan University, Taipei (China)
  2. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan) (and others)
Publication Date:
OSTI Identifier:
20929529
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 11; Other Information: DOI: 10.1103/PhysRevD.75.111101; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; B NEUTRAL MESONS; B PLUS MESONS; HADRONIC PARTICLE DECAY; LAMBDA PARTICLES; PAIR PRODUCTION; PROTONS; SIGNALS; TWO-BODY PROBLEM

Citation Formats

Tsai, Y.-T., Chang, P., Chao, Y., Hou, W.-S., Hsiung, Y. B., Lee, Y.-J., Lin, S.-W., Ueno, K., Wang, M.-Z., Abe, K., Adachi, I., Dragic, J., Haba, J., Hazumi, M., Itoh, R., Iwasaki, Y., Kichimi, H., Krokovny, P., Limosani, A., and Nakao, M. Search for B{sup 0}{yields}pp, {lambda}{lambda} and B{sup +}{yields}p{lambda} at Belle. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.111101.
Tsai, Y.-T., Chang, P., Chao, Y., Hou, W.-S., Hsiung, Y. B., Lee, Y.-J., Lin, S.-W., Ueno, K., Wang, M.-Z., Abe, K., Adachi, I., Dragic, J., Haba, J., Hazumi, M., Itoh, R., Iwasaki, Y., Kichimi, H., Krokovny, P., Limosani, A., & Nakao, M. Search for B{sup 0}{yields}pp, {lambda}{lambda} and B{sup +}{yields}p{lambda} at Belle. United States. doi:10.1103/PHYSREVD.75.111101.
Tsai, Y.-T., Chang, P., Chao, Y., Hou, W.-S., Hsiung, Y. B., Lee, Y.-J., Lin, S.-W., Ueno, K., Wang, M.-Z., Abe, K., Adachi, I., Dragic, J., Haba, J., Hazumi, M., Itoh, R., Iwasaki, Y., Kichimi, H., Krokovny, P., Limosani, A., and Nakao, M. Fri . "Search for B{sup 0}{yields}pp, {lambda}{lambda} and B{sup +}{yields}p{lambda} at Belle". United States. doi:10.1103/PHYSREVD.75.111101.
@article{osti_20929529,
title = {Search for B{sup 0}{yields}pp, {lambda}{lambda} and B{sup +}{yields}p{lambda} at Belle},
author = {Tsai, Y.-T. and Chang, P. and Chao, Y. and Hou, W.-S. and Hsiung, Y. B. and Lee, Y.-J. and Lin, S.-W. and Ueno, K. and Wang, M.-Z. and Abe, K. and Adachi, I. and Dragic, J. and Haba, J. and Hazumi, M. and Itoh, R. and Iwasaki, Y. and Kichimi, H. and Krokovny, P. and Limosani, A. and Nakao, M.},
abstractNote = {We report on a new search for two-body baryonic decays of the B meson. Improved sensitivity compared to previous Belle results is obtained from 414 fb{sup -1} of data that corresponds to 449x10{sup 6} BB pairs, which were taken on the {upsilon}(4S) resonance and collected with the Belle detector at the KEKB e{sup +}e{sup -} collider. No significant signals are observed and we set the 90% confidence level upper limits: B(B{sup 0}{yields}pp)<1.1x10{sup -7}, B(B{sup 0}{yields}{lambda}{lambda})<3.2x10{sup -7}, and B(B{sup +}{yields}p{lambda})<3.2x10{sup -7}.},
doi = {10.1103/PHYSREVD.75.111101},
journal = {Physical Review. D, Particles Fields},
number = 11,
volume = 75,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 2007},
month = {Fri Jun 01 00:00:00 EDT 2007}
}
  • We report results of a search for the charmless two-body baryonic decays B{sup 0}{yields}pp, B{sup 0}{yields}{lambda}{lambda}, and B{sup +}{yields}p{lambda} based on the analysis of a 140 fb{sup -1} data sample. We set 90% confidence level upper limits on their branching fractions: B(B{sup 0}{yields}pp)<4.1x10{sup -7}, B(B{sup 0}{yields}{lambda}{lambda})<6.9x10{sup -7}, and B(B{sup +}{yields}p{lambda})<4.9x10{sup -7}.
  • We report on a search for {lambda}{sub b}{sup 0}{yields}p{pi}{sup -} and {lambda}{sub b}{sup 0}{yields}pK{sup -} (and charge conjugate) decays in pp collisions at {radical}(s)=1.96 TeV using 193 pb{sup -1} of data collected by the CDF II experiment at the Fermilab Tevatron Collider. Data were collected using a track trigger that has been optimized to select tracks belonging to a secondary vertex that is typical of two-body charmless decays of b-flavored hadrons, including {lambda}{sub b}{sup 0} baryons. As no {lambda}{sub b}{sup 0} signal was observed, we set the upper limits on the branching fraction B({lambda}{sub b}{sup 0}{yields}ph{sup -}), where h ismore » K or {pi}, of 2.3x10{sup -5} at 90% C.L. and 2.9x10{sup -5} at 95% C.L.« less
  • We study the charmless decays B{yields}{lambda}{lambda}h, where h stands for {pi}{sup +}, K{sup +}, K{sup 0},K*{sup +}, or K*{sup 0}, using a 605 fb{sup -1} data sample collected at the {upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric energy e{sup +}e{sup -} collider. We observe B{sup 0}{yields}{lambda}{lambda}K{sup 0} and B{sup 0}{yields}{lambda}{lambda}K*{sup 0} with branching fractions of (4.76{sub -0.68}{sup +0.84}(stat){+-}0.61(syst))x10{sup -6} and (2.46{sub -0.72}{sup +0.87}{+-}0.34)x10{sup -6}, respectively. The significances of these signals in the threshold-mass enhanced mass region, M{sub {lambda}}{sub {lambda}}<2.85 GeV/c{sup 2}, are 12.4{sigma} and 9.3{sigma}, respectively. We also update the branching fraction B(B{sup +}{yields}{lambda}{lambda}K{sup +})=(3.38{sub -0.36}{sup +0.41}{+-}0.41)x10{supmore » -6} with better accuracy, and report the following measurement or 90% confidence level upper limit in the threshold-mass-enhanced region: B(B{sup +}{yields}{lambda}{lambda}K*{sup +})=(2.19{sub -0.88}{sup +1.13}{+-}0.33)x10{sup -6} with 3.7{sigma} significance; B(B{sup +}{yields}{lambda}{lambda}{pi}{sup +})<0.94x10{sup -6}. A related search for B{sup 0}{yields}{lambda}{lambda}D{sup 0} yields a branching fraction B(B{sup 0}{yields}{lambda}{lambda}D{sup 0})=(1.05{sub -0.44}{sup +0.57}{+-}0.14)x10{sup -5}. This may be compared with the large, {approx}10{sup -4}, branching fraction observed for B{sup 0}{yields}ppD{sup 0}. The M{sub {lambda}}{sub {lambda}} enhancements near threshold and related angular distributions for the observed modes are also reported.« less
  • We search for the doubly charmed baryonic decay B{sup 0}{yields}{lambda}{sub c}{sup +}{lambda}{sub c}{sup -}, in a data sample of 520x10{sup 6} BB events accumulated at the {upsilon}(4S) resonance with the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider. We find no significant signal and set an upper limit of B(B{sup 0}{yields}{lambda}{sub c}{sup +}{lambda}{sub c}{sup -})<6.2x10{sup -5} at 90% confidence level. The result is significantly below a naive extrapolation from B(B{sup -}{yields}{xi}{sub c}{sup 0}{lambda}{sub c}{sup -}) assuming a simple Cabibbo-suppression factor of |V{sub cd}/V{sub cs}|{sup 2}. The small branching fraction may be attributed to a suppression due to themore » large momentum of the baryonic decay products, which has been observed in other charmed baryonic two-body B decays.« less
  • We report the observation of B{sup -}{yields}J/{psi}{lambda}p and searches for B{sup -}{yields}J/{psi}{sigma}{sup 0}p and B{sup 0}{yields}J/{psi}pp decays, using a sample of 275x10{sup 6} BB pairs collected with the Belle detector at the {upsilon}(4S) resonance. We observe a signal of 17.2{+-}4.1 events with a significance of 11.1{sigma} and obtain a branching fraction of B(B{sup -}{yields}J/{psi}{lambda}p)=11.6{+-}2.8(stat){sub -2.3}{sup +1.8}(sys)x10{sup -6}. No signal is found for either of the two decay modes, B{sup -}{yields}J/{psi}{sigma}{sup 0}p and B{sup 0}{yields}J/{psi}pp, and upper limits for the branching fractions are determined to be B(B{sup -}{yields}J/{psi}{sigma}{sup 0}p)<1.1x10{sup -5} and B(B{sup 0}{yields}J/{psi}pp)<8.3x10{sup -7} at 90% confidence level.