Effective Lagrangian approach to weak radiative decays of heavy hadrons

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.51.1199· OSTI ID:6643585

Cheng, H; Cheung, C; Lin, G; Lin, Y C; Yan, T; Yu, H ^[1]

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1. Institute of Physics, Academia Sinica, Taipei, Taiwan 11529 (Taiwan, Province of China) Physics Department, National Central University, Chung-li, Taiwan 32054 (Taiwan, Province of China) Floyd R. Newman Laboratory of Nuclear Studies, Cornell University, Ithaca, New York 14853 (United States)

Motivated by the observation of the decay [ital [bar B]][r arrow][ital [bar K]][sup *][gamma] by the CLEO Collaboration, we have systematically analyzed the two-body weak radiative decays of bottom and charmed hadrons. There exist two types of weak radiative decays: One proceeds through the short-distance [ital b][r arrow][ital s][gamma] transition and the other occurs through [ital W] exchange accompanied by a photon emission. Effective Lagrangians are derived for the [ital W]-exchange bremsstrahlung processes at the quark level and then applied to various weak electromagnetic decays of heavy hadrons. Predictions for the branching ratios of [ital [bar B]][sup 0][r arrow][ital D][sup *0][gamma], [Lambda][sub [ital b]][sup 0][r arrow][Sigma][sub [ital c]][sup 0][gamma], [Xi][sub [ital b]][sup 0][r arrow][Xi][sub [ital c]][sup 0][gamma], and [Xi][sub [ital b]][sup 0][r arrow][Xi][prime][sub [ital b]][sup 0][gamma] are given. In particular, we find [ital scrB]([ital [bar B]][sup 0][r arrow][ital D][sup *0][gamma])[approx]0.9[times]10[sup [minus]6]. Order of magnitude estimates for the weak radiative decays of charmed hadrons, [ital D][sup 0][r arrow][ital [bar K]][sup *0][gamma], [Lambda][sub [ital c]][sup +][r arrow][Sigma][sup +][gamma], and [Xi][sub [ital c]][sup 0][r arrow][Xi][sup 0][gamma], are also presented. Within this approach, the decay asymmetry for antitriplet to antitriplet heavy baryon weak radiative transitions is uniquely predicted by heavy quark symmetry. The electromagnetic penguin contribution to [Lambda][sub [ital b]][sup 0][r arrow][Lambda][gamma] is estimated by two different methods and its branching ratio is found to be of the order of 1[times]10[sup [minus]5]. We conclude that weak radiative decays of bottom hadrons are dominated by the short-distance [ital b][r arrow][ital s][gamma] mechanism.

• OSTI ID: 6643585
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 51:3; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

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662410 -- Properties of Baryons & Baryon Resonances-- (1992-)
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTI-B NEUTRAL MESONS
ASYMMETRY
B MESONS
B NEUTRAL MESONS
BARYONS
BEAUTY PARTICLES
BOSON-EXCHANGE MODELS
BOSONS
BRANCHING RATIO
BREMSSTRAHLUNG
CHARM PARTICLES
CHARMED BARYONS
CHARMED MESONS
DECAY
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
HADRONS
INTERMEDIATE BOSONS
INTERMEDIATE VECTOR BOSONS
LAGRANGIAN FUNCTION
MATHEMATICAL MODELS
MESONS
PARTICLE DECAY
PARTICLE MODELS
PERIPHERAL MODELS
POSTULATED PARTICLES
PSEUDOSCALAR MESONS
QUARKS
RADIATIONS
RADIATIVE DECAY
W MINUS BOSONS
W PLUS BOSONS