Summary
I report results of a search for several rare few-body decays of the B-meson. For the decays B0→π+π-, B0→K+π-, and B0→K+K-, we limit the branching fractions (at 90% confidence) toB ππ<2.9·10−5,B Kπ<2.6·10−5, andB KK<0.7·10−5. While there is no statistically significant signal in any single mode, the sum ofB ππ andB Kπ exceeds zero with a significance of more than four standard deviations, indicating that we have observed charmless hadronic B-decays. We have also detected the decays Bo→K* (892)o γ and B−→K* (892)− γ, evidence for the quark-level process b→sγ. The average branching fraction is (4.5±1.5±0.9)·10−5, consistent with standard model predictions from electromagnetic penguin diagrams.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
I. Dunietz:Ann. Phys.,184, 350 (1988);M. Gronau:Phys. Rev. Lett.,63, 1451 (1989).
J. M. Gerard andW. S. Hou:Phys. Rev. D,43, 2909 (1991);H. Simma, G. Eilam andD. Wyler:Nucl. Phys. B,352, 367 (1991).
R. Fulton et al.:Phys. Rev. Lett.,64, 16 (1990);H. Albrecht et al.: Phys. Lett. B,234, 409 (1990).
J. Bartelt et al.: submitted toPhys. Rev. Lett.; Cornell Report No. CLNS 93/1240, CLEO 93-15.
H. Albrecht et al.:Phys. Lett. B,209, 119 (1988);C. Bebek et al.: Phys. Rev. Lett.,62, 8 (1989);K. Schubert:Heavy Quark Physics, edited byP. S. Drell andD. Rubin (American Institute of Physics, New York, N.Y., 1989).
D. Bortoletto et al.:Phys. Rev. Lett.,62, 2436 (1989);P. Avery et al.: Phys. Lett. B,223, 470 (1989).
H. Albrecht et al.:Phys. Lett. B,241, 278 (1990);254, 288 (1991).
M. Bauer, B. Stech andM. Wirbel:Z. Phys. C,34, 103 (1987).
M. Neubert, V. Rieckert, B. Stech andQ. P. Zu: inHeavy Flavors, edited byA. J. Buras andM. Lindner (World Scientific, Singapore, 1992). The symbols in the product are defined in this review.
N. G. Deshpande andJ. Trampetic:Phys. Rev. D,41, 895 (1990);L. L. Chau et al.: Phys. Rev. D,43, 2176 (1991).
Y. Kubota et al.:Nucl. Instrum. Methods A,320, 66 (1992).
We use muon pairs to determine the momentum resolution at 5.3 GeV/c, and the decay modes B→ϕK, B→Dπ, and B→D*π to determine the momentum resolution in the range 1.5–2.5 GeV/c.
R. A. Fisher:Ann. Eugen.,7, 179 (1936);M. G. Kendall andA. Stuart:The Advanced Theory of Statistics, 2nd edition (Hafner, New York, N.Y., 1968), Vol. III, §44.5ff.
M. K. Gaillard andB. W. Lee:Phys. Rev. Lett.,33, 108 (1974);G. Altarelli andL. Maiani:Phys. Lett. B,52, 351 (1974);J. Ellis, M. K. Gaillard andD. V. Nanopoulos:Nucl. Phys. B,100, 313 (1975);A. I. Vainshtein, V. I. Zakharov andM. A. Shifman:JETP Lett.,22, 55 (1975).
F. Gilman andM. B. Wise:Phys. Lett. B,83, 83 (1979).
B. A. Campbell andP. J. O'Donnell:Phys. Rev. D,25, 1989 (1982);M. Bander, D. Silverman andA. Soni:Phys. Rev. Lett.,43, 242 (1979). For a review, seeJ. Rosner: Enrico Fermi Institute report, EFI 90-63 (1990).
S. Bertolini, F. Borzumati andA. Masiero:Phys. Rev. Lett.,59, 180 (1987);N. G. Deshpande et al.: Phys. Rev. Lett.,59, 183 (1987);B. Grinstlein, R. Springer andM. B. Wise:Phys. Lett. B,202, 138 (1988);R. Grigjanis et al.: Phys. Lett. B,213, 355 (1988);A. Ali andC. Greub:Z. Phys. C,49, 431 (1991).
N. G. Deshpande et al.:Phys. Lett. B,214, 467 (1988);P. Colangelo et al.: Z. Phys. C,45, 575 (1990).
S. Bertolini et al.:Nucl. Phys. B,353, 591 (1991);J. L. Hewett:Phys. Rev. Lett.,70, 1045 (1993);V. Barger et al.: Phys. Rev. Lett.,70, 1368 (1993).
T. Altomari:Phys. Rev. D,37, 677 (1988);C. A. Dominguez et al.: Phys. Lett. B,214, 459 (1988);N. G. Deshpande et al.: Z. Phys. C,40, 369 (1988);T. M. Aliev et al.: Phys. Lett. B,237, 569 (1990);P. J. O'Donnell andH. Tung:Phys. Rev. D,44, 741 (1991);A. Ali andC. Greub:Phys. Lett. B,259, 182 (1991);A. Ali, T. Ohl andT. Mannel:Phys. Lett. B,298, 194 (1993).
We use K* to denote K*(892) from here on.
R. Ammar et al.:Phys. Rev. Lett.,71, 674 (1993).
G. Fox andS. Wolfram:Phys. Rev. Lett.,41, 1581 (1978).
S ⊥ is defined as the sum of the magnitudes of the momenta transverse to the photon direction, summed over all particles more than 45° away from the photon axis, divided by the sum of the magnitudes of the momenta of all particles except the photon.
This is 25.4×1.464+0.464, where 0.464 is the scale factor between off-resonance and on-resonance data samples.
The Poisson probability that a mean of 1.1 gives rise to 8 or more events is 2.0·10−5, but this estimate of significance does not consider the statistical error on the background, while the procedure with binomial probability does.
The binomial probabilities for continuum plus\(B\bar B\) backgrounds fluctuating up to the numbers of observed signal events are larger than the probabilities for continuum background alone by at most a factor of 4 for the K*0γ mode, and a factor of 1.4 for the K*− γ modes.
Author information
Authors and Affiliations
Consortia
Rights and permissions
About this article
Cite this article
CLEO Collaboration., Ehrlich, R.D. Recent results form CLEOII. Nuov Cim A 107, 1977–1987 (1994). https://doi.org/10.1007/BF02823592
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF02823592