Heavy baryon production and decay

Dunietz, Isard

doi:10.1103/physrevd.58.094010

Cited by 32 publications

(34 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These measurements supported the prediction [3] that the final states with Λ c baryons are not the only sizable contributions to the baryonic B-meson decay rate, and that the charm-meson modes of the form B→D ( * ) NN ′ +anything, where the N (′) represent nucleon states, are also significant. Previous measurements show a trend that the branching fractions increase with the number of final-state particles.…”

supporting

confidence: 69%

Observation and study of the baryonicB-meson decaysB→D()pp¯
Sanchez¹,
Lees²,
Poireau³
et al. 2012
Phys. Rev. D*
21
0
6
0
View full text Add to dashboard Cite

We present results for B-meson decay modes involving a charm meson, protons, and pions using 455×10 6 BB pairs recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e + e − collider. The branching fractions are measured for the following ten decays:, and B − →D * + ppπ − π − . The four B − and the two five-body B 0 modes are observed for the first time. The four-body modes are enhanced compared to the three-and the five-body modes. In the three-body modes, the M (pp) and M (D ( * )0 p) invariant mass distributions show enhancements near threshold values. In the four-body mode B 0 →D + ppπ − , the M (pπ − ) distribution shows a narrow structure of unknown origin near 1.5 GeV/c 2 . The distributions for the five-body modes, in contrast to the others, are similar to the expectations from uniform phase-space predictions.

show abstract

supporting

confidence: 69%

Observation and study of the baryonicB-meson decaysB→D()pp¯
Sanchez¹,
Lees²,
Poireau³
et al. 2012
Phys. Rev. D*
21
0
6
0
View full text Add to dashboard Cite

show abstract

“…This assumption was called into question in Ref. [1]. The second relies upon measurement of the ratio (10) and the assumptions that (i) the semileptonic decay of Λ c is saturated by the Λe + ν e final state, and (ii) all inclusive semileptonic decay rates of charmed particles are equal.…”

Section: Remarks On the Modementioning

confidence: 99%

“…We have denoted the (initial,final) Λ by Λ (1,2) with four-momentum P (1,2) , mass M (1,2) , and covariant four-velocity v (1,2) = P (1,2) /M (1,2) . The four-momentum transfer to the lepton pair is q = P 1 − P 2 .…”

Section: Form Factors Inmentioning

confidence: 99%

See 1 more Smart Citation

Prospects for improvedΛcbranching fractions

Rosner

2012

Phys. Rev. D

View full text Add to dashboard Cite

The experimental uncertainty on the branching fraction B(Λ c → pK − π + ) = (5.0 ± 1.3)% has not decreased since 1998, despite a much larger data sample. Uncertainty in this quantity dominates that in many other quantities, including branching fractions of Λ c to other modes, branching fractions of b-flavored baryons, and fragmentation fractions of charmed and bottom quarks. Here we advocate a lattice QCD calculation of the form factors in Λ c → Λℓ + ν ℓ (the case ℓ = e + is simpler as the mass of the lepton can be neglected). Such a calculation would yield an absolute prediction for the rate for Λ c → Λℓ + ν ℓ . When combined with the Λ c lifetime, it could provide a calibration for an improved set of Λ c branching fractions as long as the accuracy exceeds about 25%.PACS numbers: 14.20.Lq, 14.65.Dw, 13.30.Ce, 12.38.Gc I INTRODUCTIONDespite the accumulation of a vastly greater sample of charmed particles in e + e − , ep, and hadron-hadron collisions, the most accurately known branching fraction for the decay of the lowest-lying charmed baryon Λ c , B(Λ c → pK − π + ) = (5.0 ± 1.3)%, has remained at the same value since 1998. It was only pinned down to that accuracy thanks to constructive suggestions by Dunietz [1]. This branching fraction sets the scale for a number of other quantities which depend on it. Many other Λ c branching fractions are measured through their ratio to the pK − π + mode [2]. It sets the scale for b-flavored baryon branching fractions, and governs fragmentation fractions of charm and bottom quarks into baryons.In the present paper we advocate improvement of accuracy of the semileptonic branching fraction B(Λ c → Λe + ν e ), whose current value is (2.1 ± 0.6)%, via a lattice QCD calculation of the relevant form factors. Such calculations have been performed for the semileptonic decays of charmed mesons, D → Kℓν ℓ and D → πℓν ℓ [3], which are characterized by two form factors. Although four form factors are relevant to Λ c → Λℓν ℓ in the limit of zero lepton mass, the difficulty of such a calculation is outweighed by its importance. A calculation enabling the prediction of the rate for Λ c → Λe + ν e (and hence its branching fraction, given τ (Λ c ) = 200 ± 6 fs [2]) to an accuracy of better than about 25% would represent an improvement on a wide variety of key quantities.In Section II we review various quantities which could profit from improvement in the accuracy of B(Λ c → Λe + ν e ). We discuss in Section III the present status of understanding of form factors in this decay. The corresponding semileptonic decay Λ b → Λ c e −ν e , to which the Heavy Quark Effective Theory (HQET) can be applied, is treated in Section IV. Some remarks are made in Section V regarding the "calibrating" mode Λ c → pK − π + , while Section V concludes.

show abstract

“…Three-body baryonic decay in b → c transitions have been observed [2] previously, following a suggestion by Dunietz [3]. It is interesting to compare the charmless case to the charmful one and also to charmless two-body modes such as B 0 → pp, which has B < 1.2 × 10 −6 [4].…”

Section: Introductionmentioning

confidence: 99%

Charmless three-body baryonicBdecays

2002

View full text Add to dashboard Cite

Motivated by recent data on B → ppK decay, we study various charmless three-body baryonic B decay modes, including Λpπ, Σ 0p π, ppπ, ppK 0 , in a factorization approach. These modes have rates of order 10 −6 . There are two mechanisms for the production of baryon pairs: current-produced and transition. The behavior of decay spectra from these baryon production mechanisms can be understood by using QCD counting rules. Predictions on rates and decay spectra can be checked in the near future.

show abstract

Heavy baryon production and decay

Cited by 32 publications

References 31 publications

Observation and study of the baryonicB-meson decaysB→D()pp¯
Sanchez¹,
Lees²,
Poireau³
et al. 2012
Phys. Rev. D*
21
0
6
0
View full text Add to dashboard Cite

Observation and study of the baryonicB-meson decaysB→D()pp¯
Sanchez¹,
Lees²,
Poireau³
et al. 2012
Phys. Rev. D*
21
0
6
0
View full text Add to dashboard Cite

Prospects for improvedΛcbranching fractions

Charmless three-body baryonicBdecays

Contact Info

Product

Resources

About

Heavy baryon production and decay

Cited by 32 publications

References 31 publications

Observation and study of the baryonicB-meson decaysB→D(*)pp¯Sanchez1, Lees2, Poireau3 et al. 2012Phys. Rev. D21060View full textAdd to dashboardCite

Observation and study of the baryonicB-meson decaysB→D(*)pp¯Sanchez1, Lees2, Poireau3 et al. 2012Phys. Rev. D21060View full textAdd to dashboardCite

Prospects for improvedΛcbranching fractions

Charmless three-body baryonicBdecays

Contact Info

Product

Resources

About

Observation and study of the baryonicB-meson decaysB→D()pp¯
Sanchez¹,
Lees²,
Poireau³
et al. 2012
Phys. Rev. D*
21
0
6
0
View full text Add to dashboard Cite

Observation and study of the baryonicB-meson decaysB→D()pp¯
Sanchez¹,
Lees²,
Poireau³
et al. 2012
Phys. Rev. D*
21
0
6
0
View full text Add to dashboard Cite