共查询到20条相似文献,搜索用时 62 毫秒
1.
Jian-Bin Chen Meng Zhang Li-Li Xing Tai-Fu Feng Shu-Min Zhao Ke-Sheng Sun 《中国物理C(英文版)》2021,(5):39-48
Applying the effective Lagrangian method,we study the flavor changing neutral current process b→ sγwithin the minimal supersymmetric extension of the Standard Model,where baryon and lepton numbers are local gauge symmetries.Constraints on the parameters are investigated numerically with the experimental data for the branching ratio of B→ X_sγ.Additionally,we present the corrections to direct CP-violation in B→ X_sγ and time-dependent CP-asymmetry in B→K~*γ.With appropriate assumptions on the parameters,we find the direct CP-violation Acp is very small,while one-loop contributions to S_(K~*_γ) can be significant. 相似文献
2.
Dong-Sheng Du Xue-Qian Li Zheng-Tao Wei Bing-Song Zou 《The European Physical Journal A - Hadrons and Nuclei》1999,4(1):91-96
We study the final-state interactions in B →π K decays through B → VV →π K processes where the inelastic rescattering occurs
via single pion exchange. The next-to-leading order low-energy effective Hamiltonian and Bauer-Stech-Wirbel (BSW) model are
used to evaluate the weak transition matrix elements and final-state interactions. We found that the final-state interaction
effects in B →ρ K*→π K processes are significant. The Fleischer-Mannel relation for the Cabibbo-Kobayashi-Maskawa (CKM) angle γ can be significantly
modified.
Received: 13 August 1998 相似文献
3.
本文给出了过程e~+e~-→J/ψ→γB,B→P_1P_2的螺旋性形式(HF)~[1]和等效相互作用形式(EIF)~[2]之间的关系.在B的不同自旋(J=2,4)下赝标介子的角分布显示,为了确定B的自旋,存在敏感区域和不敏感区域.令人遗憾的是,θ/f_2(1720)和ξ(2230)的数据正好掉入不敏感区域. 相似文献
4.
Using the QCD factorization approach, we investigate the large branching ratios of B→ηK^* decays and the SCKs anomaly of B→φKs decay in the two Higgs doublet model Ⅲ. With the contributions of flavour-changing neutral current mediated by the neutral Higgs bosons H^0, h^0 and A^0 at the tree level, we provide a coherent resolution to these anomalies within the constrained parameter spaces, which are 120 〈|λbs λss| 〈136. This will be really interesting in searching for the signs of new physics. 相似文献
5.
We calculate direct CP-violating rate asymmetries in chargedB→PP andB→VP decays arising from the interference of amplitudes with different strong and CKM phases. The perturbative strong phases develop at order α s from absorptive parts of one-loop matrix elements of the next-to-leading logarithm corrected effective Hamiltonian. CPT constraints are maintained. Based on this model, we find that partial rate asymmetries between charge conjugateB ± decays can be as high as 20% for certain channels with branching ratios in the 10?6 range. Because the $c\bar c$ threshold lies so close to the physical momentum scale, the asymmetries depend sensitively on the model assumptions used to evaluate the imaginary parts of the matrix elements, in particular, on the internal momentum transfer. The charge asymmetries of partial rates would provide unambiguous evidence for direct CP violation. 相似文献
6.
We study the unexpectedly large rate for the factorization-forbidden decay B→χc0K within the QCD
factorization approach. We use a non-zero gluon mass to regularize
the infrared divergences in vertex corrections. The end-point
singularities arising from spectator corrections are regularized and carefully estimated by the off-shellness of quarks. We find
that the contributions arising from the vertex and leading-twist spectator corrections are numerically small, and the twist-3 spectator contribution with chiral enhancement and linear
end-point singularity becomes dominant. With reasonable choices for the parameters, the branching ratio for B→χc0K decay is estimated to be in the range (2~4)×10-4, which is compatible with the Belle and BaBar data. 相似文献
7.
8.
Recently, the first evidence for the decay B s 0 → μ + μ ? has been announced by the LHCb Collaboration and the measured branching ratio B( s 0 → μ +) = (3.2 ?1.2 +1.5 ) × 10?9 is in good agreement with the standard model (SM) expectation. It has also reported an upper limit for B(B d 0 → μ + μ ?) < 9.4 × 10?10 at 95% confidence level. In this paper, we study the B s 0 → μ + μ ? and B d 0 → μ + μ ? rare decays in flavor-changing Z′ model. Our estimated branching ratios are enhanced from their SM values and provide signals for new physics. 相似文献
9.
《Physics letters. [Part B]》1988,207(1):106-108
Recently reported decays of the B→pp̄π and pp̄ππ have been interpreted as evidence for the b→u transition. It is shown that a certain class of b→c transitions could be misidentified and interpreted as B→pp̄π(π). 相似文献
10.
Hoi CT Chang P Aihara H Asner DM Aushev T Bakich AM Belous K Bhardwaj V Bhuyan B Bischofberger M Bondar A Bozek A Bračko M Browder TE Chang MC Chao Y Chen A Chen KF Chen P Cheon BG Chilikin K Cho K Choi Y Danilov M Drásal Z Drutskoy A Eidelman S Fast JE Gaur V Gabyshev N Goh YM Golob B Haba J Hayasaka K Hoshi Y Hou WS Hsiung YB Hyun HJ Inami K Ishikawa A Iwabuchi M Iwasaki Y Iwashita T Kang JH Kawasaki T Kim HJ Kim HO Kim JB Kim JH Kim KT Kim MJ Kinoshita K Ko BR Kobayashi N Kodyš P Korpar S 《Physical review letters》2012,108(3):031801
We report measurements of the branching fractions and CP asymmetries for B(±)→ηh(±) (h=K or π) and the observation of the decay B(0)→ηK(0) from the final data sample of 772×10(6) B ?B pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The measured branching fractions are B(B(±)→ηK(±))=(2.12±0.23±0.11)×10(-6), B(B(±)→ηπ(±))=(4.07±0.26±0.21)×10(-6), and B(B(0)→ηK(0))=(1.27(-0.29)(+0.33)±0.08)×10(-6), where the last decay is observed for the first time with a significance of 5.4 standard deviations (σ). We also find evidence for CP violation in the charged B modes, A(CP)(B(±)→ηK(±))=-0.38±0.11±0.01 and A(CP)(B(±)→ηπ(±))=-0.19±0.06±0.01 with significances of 3.8 σ and 3.0 σ, respectively. For all measurements, the first and second uncertainties are statistical and systematic, respectively. 相似文献
11.
Nishimura K Browder TE Adachi I Aihara H Arinstein K Aushev T Bakich AM Balagura V Barberio E Belous K Bhardwaj V Bischofberger M Bondar A Bozek A Bračko M Chang MC Chao Y Chen A Chen KF Chen P Cheon BG Chiang CC Cho IS Choi Y Dalseno J Danilov M Doležal Z Drutskoy A Eidelman S Gabyshev N Golob B Ha H Haba J Hara T Hayasaka K Hayashii H Horii Y Hoshi Y Hou WS Hyun HJ Iijima T Inami K Itoh R Iwabuchi M Iwasaki Y Joshi NJ Julius T Kang JH Kapusta P Kawai H Kawasaki T Kichimi H Kiesling C Kim HJ 《Physical review letters》2010,105(19):191803
We report a first measurement of inclusive B→Xsη decays, where Xs is a charmless state with unit strangeness. The measurement is based on a pseudoinclusive reconstruction technique and uses a sample of 657×10(6)BB pairs accumulated with the Belle detector at the KEKB e+e- collider. For MXs < 2.6 GeV/c2, we measure a branching fraction of [26.1±3.0(stat)-2.1+1.9(syst)-7.1+4.0(model)]×10(-5) and a direct CP asymmetry of ACP=-0.13±0.04-0.03+0.02. Over half of the signal occurs in the range MXs > 1.8 GeV/c2. 相似文献
12.
Strong UV emission has been observed in the reactions of XeF2+SiH4+F2 and XeF2+B2H6+F2. The emission spectra have been identified with the B
2X
2 transition of XeF. Possible mechanisms of XeF(B) production are discussed. 相似文献
13.
14.
A. Ali B.D. Pecjak C. Greub 《The European Physical Journal C - Particles and Fields》2008,55(4):577-595
We compute NNLO ((αs
2)) corrections to the hard-scattering kernels entering the QCD factorization formula for B→Vγ decays, where V is a light vector
meson. We give complete NNLO results for the dipole operators Q7 and Q8, and partial results for Q1 valid in the large-β0 limit and neglecting the NNLO correction from hard-spectator scattering. Large perturbative logarithms in the hard-scattering
kernels are identified and resummed using soft-collinear effective theory. We use our results to estimate the branching fractions
for B→K*γ and Bs→φγ decays at NNLO and compare them with the current experimental data. 相似文献
15.
We study the rare B decay B→K*ℓ+ℓ- using soft-collinear effective theory (SCET). At leading power in 1/mb, a factorization formula is obtained valid to all orders in αs. For phenomenological application, we calculate the decay amplitude including order αs corrections, and resum the logarithms by evolving the matching coefficients from the hard scale
down to the scale
. The branching ratio for B→K*ℓ+ℓ- is uncertain due to the imprecise knowledge of the soft form factors ζ⊥(q2) and ζ∥(q2). Constraining the soft form factor ζ⊥(q2=0) from data on B→K*γ yields ζ⊥(q2=0)=0.32±0.02. Using this input, together with the light-cone sum rules to determine the q2-dependence of ζ⊥(q2) and the other soft form factor ζ∥(q2), we estimate the partially integrated branching ratio in the range 1 GeV2≤q2≤7 GeV2 to be (2.92+0.67
-0.61)×10-7. We discuss how to reduce the form factor related uncertainty by combining data on B→ρ(→ππ)ℓνℓ and B→K*(→Kπ)ℓ+ℓ-. The forward-backward asymmetry is less sensitive to the input parameters. In particular, for the zero-point of the forward-backward
asymmetry in the standard model, we get q0
2=(4.07+0.16
-0.13)
GeV2. The scale dependence of q0
2 is discussed in detail.
PACS 13.25.Hw, 12.39.St, 12.38.Bx 相似文献
16.
本文给出了过程e+e-→J/ψ→γB,B→P1P2的螺旋性形式(HF)[1]和等效相互作用形式(EIF)[2]之间的关系.在B的不同自旋(J=2,4)下赝标介子的角分布显示,为了确定B的自旋,存在敏感区域和不敏感区域.令人遗憾的是,θ/f2(1720)和ξ(2230)的数据正好掉入不敏感区域. 相似文献
17.
Abazov VM Abbott B Acharya BS Adams M Adams T Alexeev GD Alkhazov G Alton A Alverson G Alves GA Aoki M Arov M Askew A Åsman B Atramentov O Avila C BackusMayes J Badaud F Bagby L Baldin B Bandurin DV Banerjee S Barberis E Baringer P Barreto J Bartlett JF Bassler U Bazterra V Beale S Bean A Begalli M Begel M Belanger-Champagne C Bellantoni L Beri SB Bernardi G Bernhard R Bertram I Besançon M Beuselinck R Bezzubov VA Bhat PC Bhatnagar V Blazey G Blessing S Bloom K Boehnlein A Boline D Boos EE 《Physical review letters》2011,107(12):121802
We present a measurement of the ratio of top quark branching fractions R=B(t→Wb)/B(t→Wq), where q can be a d, s, or b quark, in the lepton+jets and dilepton tt final states. The measurement uses data from 5.4 fb(-1) of pp collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure R=0.90±0.04, and we extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element |V(tb)| as |V(tb)|=0.95±0.02, assuming unitarity of the 3×3 CKM matrix. 相似文献
18.
Aaij R Abellan Beteta C Adeva B Adinolfi M Adrover C Affolder A Ajaltouni Z Albrecht J Alessio F Alexander M Alkhazov G Alvarez Cartelle P Alves AA Amato S Amhis Y Anderson J Appleby RB Aquines Gutierrez O Archilli F Arrabito L Artamonov A Artuso M Aslanides E Auriemma G Bachmann S Back JJ Bailey DS Balagura V Baldini W Barlow RJ Barschel C Barsuk S Barter W Bates A Bauer C Bauer T Bay A Bediaga I Belous K Belyaev I Ben-Haim E Benayoun M Bencivenni G Benson S Benton J Bernet R Bettler MO 《Physical review letters》2012,108(10):101601
A search is performed for the lepton number violating decay B+ → h- μ+ μ+, where h- represents a K- or a π-, using an integrated luminosity of 36 pb(-1) of data collected with the LHCb detector. The decay is forbidden in the standard model but allowed in models with a Majorana neutrino. No signal is observed in either channel and limits of B(B+ → K- μ+ μ+) < 5.4×10(-8) and B(B+ → π- μ+ μ+) < 5.8×10(-8) are set at the 95% confidence level. These improve the previous best limits by factors of 40 and 30, respectively. 相似文献
19.
20.
We study the effect of hard-core repulsion (known as the bus effect) betweenB particles on the reaction-diffusion systemA+BB in the continuous-time random walk model in one dimension with theA particles stationary. We show rigorously that the survival probability of theA particles is asymptotically bounded asC
1lim
t{[–logS(t)]/t
0.5}C
2, whereC
1 andC
2 are constants. We also do simulations to confirm our results. 相似文献