B粒子的四体重子衰变研究：B→pp¯π+π-，Λp¯π+π-和Λp¯K+K-

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"这篇研究论文详细探讨了B粒子的四体重子衰变过程，特别是B→B1B′2M1M2类型的衰变，其中B1和B2代表无魅力重子，而M1和M2则表示介子。研究基于LHCb实验的最新观察结果，该实验表明这些衰变主要通过B→M1M2跃迁伴随着重子对的产生来完成。研究团队计算得出B-衰变成Λp¯π+π-的概率为(3.7+1.5-1.0)×10-6，B¯0衰变成pp¯π+π-和pp¯π+K-的概率分别为(3.0±0.9)×10-6和(6.6±2.4)×10-6，这些结果与现有的实验数据相符。此外，他们还预测了B-衰变成Λp¯K+K-的概率为(3.0+1.3-0.9)×10-6，这为LHCb和BELLE实验提供了可检测的可能性。" 这篇在《Physics Letters B》期刊上发表的文章深入研究了B粒子的四体衰变机制，特别是在无魅力重子和介子参与的环境中。B粒子的衰变通常涉及到复杂的粒子生成和相互作用，这种衰变过程对于理解基本粒子物理学中的强相互作用有重要意义。研究人员采用的分析方法考虑了LHCb实验的观测数据，这是一种位于欧洲核子研究中心(CERN)的大强子对撞机(LHC)上的粒子探测器，专门用于研究B介子的性质。通过对B-衰变到Λp¯π+π-的分析，研究人员得出了相应的衰变速率，这有助于验证标准模型的预测并可能揭示超出标准模型的新物理现象。同时，对B¯0衰变的预测提供了关于B介子家族衰变模式的更多信息，这对于进一步探索量子色动力学(QCD)的动态过程至关重要。预测B-衰变成Λp¯K+K-的概率不仅增加了实验验证的可能性，也为未来的粒子物理实验提供了新的研究目标。LHCb和BELLE实验有能力探测这些高精度的衰变率，这将有助于改进我们对重子衰变的理解，从而推进粒子物理学领域的理论与实验研究。这项研究通过详尽的理论计算和数据分析，深入探讨了B粒子的四体重子衰变过程，这些发现对于粒子物理学的理论框架，尤其是强相互作用的理论模型有着深远的影响。通过对比实验数据和理论预测，我们可以更好地理解和测试标准模型，同时寻找可能存在的新物理线索。

Physics Letters B 770 (2017) 348–351

Contents lists available at ScienceDirect

Physics Letters B

www.elsevier.com/locate/physletb

Four-body baryonic decays of B → p

pπ

−

(π

−

) and



pπ

−

)

Y.K. Hsiao

a,b

, C.Q. Geng

a,b,c,∗

Chongqing University of Posts & Telecommunications, Chongqing, 400065, China

Department of Physics, National Tsing Hua University, Hsinchu, 300, Taiwan

Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Hunan Normal University, Changsha 410081, China

a r t i c l e i n f o a b s t r a c t

Article history:

Received

7 April 2017

Accepted

25 April 2017

Available

online 28 April 2017

Editor: J.

Hisano

We study the four-body baryonic B → B

decays with B

1,2

) being charmless baryons

(mesons). In accordance with the recent LHCb observations, each decay is considered to proceed

through the B → M

transition together with the production of a baryon pair. We obtain that

B(B

−

→

pπ

−

) =(3.7

+1.5

−1.0

) ×10

−6

and B(

→ p

pπ

−

, p

pπ

−

) =(3.0 ±0.9, 6.6 ±2.4) ×10

−6

in agreement with the data. We also predict B(B

−

→

−

) = (3.0

+1.3

−0.9

) ×10

−6

, which is accessible

to the LHCb and BELLE experiments.

(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP

1. Introduction

One of the main purposes of the B factories and current LHCb

is to study CP violation (CPV), which is important for us to under-

stand

the puzzle of the matter–antimatter asymmetry in the Uni-

verse.

As the observables, the (in)direct CP-violating asymmetries

(CPAs) require both weak and strong phases [1–3], whereas the

T-violating triple momentum product correlations (TPCs), such as



·(



) in a four-body decay, do not necessarily need a strong

phase [4,5]. For example, the LHCb Collaboration has provided the

ﬁrst evidence for CPV from the TPCs in 

→ pπ

−

[6], and

measured TPCs in 

→ pK

−

[7]. As the similar baryonic

cases, the four-body baryonic B decays can also provide TPCs.

For

a long time, the B

−

→ 

pπ

−

decay was the only ob-

served

decay mode in B → B

[8]. Until very recently,

more four-body baryonic B decays have been observed by the

LHCb [9], which motivate us to give theoretical estimations on the

corresponding decay branching ratios. The experimental measure-

ments

for the branching ratios of

−

→B

at the level

of 10

−6

are given by [8,9]

→ p

pπ

−

) =(3.0 ±0.2 ±0.2 ±0.1) ×10

−6

→ p

∓

) =(6.6 ±0.3 ±0.3 ±0.3) ×10

−6

Corresponding author.

E-mail

address: geng@phys.nthu.edu.tw (C.Q. Geng).

B(B

−

→

pπ

−

) =(5.92

+0.88

−0.84

±0.69) × 10

−6

, (1)

where the resonant B(B

−

→ 

p (ρ

, f

(1270) →)π

−

) have

been excluded from the data [8]. In comparison with B(

→

−

)  (1.3 ± 0.3) × 10

−7

and B(

→ p

pπ

−

) < 7.3 ×

−7

(90% C.L.) [9], the decays with B ∼ 10

−6

in Eq. (1) are

recognized to have the same theoretical correspondence, where

−

→ B

proceed through the B → M

transi-

tion

along with the B

production, as depicted in Fig. 1. Note

that the

decays of

→ p

∓

and p

−

with

s be-

ing

replaced by

d in

→ p

pπ

−

and p

∓

have also

been found with the branching ratios of order 10

−6

[9], respec-

tively.

this report, we will calculate the four-body baryonic B de-

cays

in accordance with the decaying processes in Fig. 1, with

the extraction of the B → M

transition form factors from the

B → D

(∗)

and B → M

decays and the adoption of the

timelike baryonic form factors from the two-body and three-body

baryonic B decays. Our theoretical approach will be useful for the

estimations of TPCs in B → B

to be compared to future

measurements by the LHCb.

2. Formalism

In terms of the quark-level effective Hamiltonian for the charm-

less

b → q

transition, the amplitudes of the four-body bary-

onic

B decays by the generalized factorization approach are de-

rived

as [10]

http://dx.doi.org/10.1016/j.physletb.2017.04.067

0370-2693/

SCOAP

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