P. Chen, M. -Z. Wang, I. Adachi, H. Aihara, D. M. Asner, V. Aulchenko, T. Aushev, A. M. Bakich, E. Barberio, K. Belous, B. Bhuyan, A. Bozek, M. Bračko, T. E. Br… 展开作者
P. Chen, M. -Z. Wang, I. Adachi, H. Aihara, D. M. Asner, V. Aulchenko, T. Aushev, A. M. Bakich, E. Barberio, K. Belous, B. Bhuyan, A. Bozek, M. Bračko, T. E. Browder, M. -C. Chang, P. Chang, Y. Chao, A. Chen, B. G. Cheon, I. -S. Cho, K. Cho, Y. Choi, J. Dalseno, M. Danilov, Z. Doležal, Z. Drásal, S. Eidelman, J. E. Fast, M. Feindt, V. Gaur, Y. M. Goh, J. Haba, T. Hara, K. Hayasaka, H. Hayashii, Y. Hoshi, W. -S. Hou, Y. B. Hsiung, H. J. Hyun, A. Ishikawa, R. Itoh, M. Iwabuchi, Y. Iwasaki, T. Iwashita, T. Julius, J. H. Kang, P. Kapusta, N. Katayama, T. Kawasaki, H. Kichimi, C. Kiesling, H. O. Kim, J. B. Kim, J. H. Kim, K. T. Kim, M. J. Kim, Y. J. Kim, K. Kinoshita, B. R. Ko, N. Kobayashi, S. Koblitz, P. Križan, T. Kuhr, A. Kuzmin, Y. -J. Kwon, J. S. Lange, S. -H. Lee, J. Li, Y. Li, J. Libby, C. Liu, Y. Liu, D. Liventsev, R. Louvot, D. Matvienko, S. McOnie, H. Miyata, Y. Miyazaki, G. B. Mohanty, Y. Nagasaka, E. Nakano, M. Nakao, Z. Natkaniec, S. Neubauer, S. Nishida, O. Nitoh, S. Ogawa, T. Ohshima, S. L. Olsen, Y. Onuki, P. Pakhlov, G. Pakhlova, H. Park, H. K. Park, T. K. Pedlar, R. Pestotnik, M. Peters, M. Petrič, L. E. Piilonen, M. Ritter, M. Röhrken, S. Ryu, H. Sahoo, Y. Sakai, T. Sanuki, O. Schneider, C. Schwanda, K. Senyo, M. E. Sevior, M. Shapkin, C. P. Shen, T. -A. Shibata, J. -G. Shiu, B. Shwartz, F. Simon, J. B. Singh, P. Smerkol, Y. -S. Sohn, E. Solovieva, S. Stanič, M. Starič, M. Sumihama, T. Sumiyoshi, G. Tatishvili, Y. Teramoto, M. Uchida, S. Uehara, Y. Unno, S. Uno, G. Varner, K. E. Varvell, C. H. Wang, X. L. Wang, Y. Watanabe, K. M. Williams, E. Won, B. D. Yabsley, Y. Yamashita, M. Yamauchi, Z. P. Zhang
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6 pages, 4 figures (6 figure files), submitted to Phys.Rev.D
We study B- meson decays to pbar Lambda D(*)0 final states using a sample of 657 * 10^6 B Bbar events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider. The observed branching fraction for B- to pbar Lambda D0 is (1.43^ +0.28_-0.25 +- 0.18)*10^-5. with a significance of 8.1 standard deviations, where the uncertainties are statistical and systematic, respectively. Most of the signal events have the pbarLambda mass peaking near threshold. No significant signal is observed for B- to pbar Lambda D*0 and the corresponding upper limit on the branching fraction is 4.8 * 10^-5 at the 90% confidence level.
We report a measurement of the lifetime of the Lambda_b baryon in decays to the Lambda_C+ pi- final state in a sample corresponding to 1.1 fb^-1 collected in p-pbar collisions at sqrt(s) = 1.96 TeV by the CDF II detector at the Tevatron collider. Using a sample of about 3000 fully reconstructed Lambda_b events we measure tau(Lambda_b) = 1.401 +- 0.046 (stat) +- 0.035 (syst) ps (corresponding to c.tau(Lambda_b) = 420.1 +- 13.7 (stat) +- 10.6 (syst) um, where c is the speed of light). The ratio of this result and the world average B^0 lifetime yields tau(Lambda_b)/tau(B^0) = 0.918 +- 0.038 (stat…
Search for Lambda_b -> p pi and Lambda_b -> p K decays in p-pbar collisions at sqrt(s) = 1.96 TeV
本文利用费米实验室Tevatron对撞机上CDFII实验收集的193 pb-1数据，研究了sqrt（s）= 1.96 TeV的p-pbar碰撞中Lambda_b-> p π-和Lambda_b -> p K-（和电荷共轭）衰变.数据收集使用的轨道触发器，已被优化，以选择属于一个次要的顶点，这是典型的两个体的魅力衰变的b味强子，包括Lambda_b重子的轨道。由于没有观察到Lambda_b信号，我们将分支分数BR（Lambda_b -> ph-）的上限设定为2.3 × 10 -5，其中h是K或pi，在90% C. L. 95% C.L.时为2.9x10-5。
Using a sample of $1.06\times10^8$ $ψ^\prime$ mesons collected with the BESIII detector at the BEPCII $e^+e^-$ collider and $χ_{cJ}$ mesons produced via radiative transitions from the $ψ^\prime$, we report the first observation for $ψ^\prime\to \bar{p}K^+Σ^0 +c.c.$ (charge-conjugate), as well as improved measurements for the $χ_{cJ}$ hyperon decays $χ_{cJ}\to\bar{p}K^+Λ+c.c.$. The branching fractions are measured to be $\mathcal{B}(ψ^\prime\to \bar{p}K^+Σ^0+c.c)= (1.67\pm0.13\pm0.12)\times10^{-5}$, $\mathcal{B}(χ_{c0}\to\bar{p}K^+Λ+c.c.)= (13.2\pm0.3\pm1.0)\times10^{-4}$, $\mathcal{B}(χ_{c1}\t…
We report measurements of the inclusive transverse momentum pT distribution of centrally produced kshort, kstar(892), and phi(1020) mesons up to pT = 10 GeV/c in minimum-bias events, and kshort and lambda particles up to pT = 20 GeV/c in jets with transverse energy between 25 GeV and 160 GeV in pbar p collisions. The data were taken with the CDF II detector at the Fermilab Tevatron at sqrt(s) = 1.96 TeV. We find that as pT increases, the pT slopes of the three mesons (kshort, kstar, and phi) are similar, and the ratio of lambda to kshort as a function of pT in minimum-bias events becomes simil…
Observation of B+ -> p pbar pi+, B0 -> p pbar K0, and B+ -> p pbar K*+
We report the first observation of a b -> u type charmless baryonic B decay, B+ -> p pbar pi+, as well as b -> s type B0 -> p pbar K0 and B+ -> p pbar K*+ decays. The analysis is based on a 78fb^{-1} data sample recorded on the Upsilon(4S) resonance with the Belle detector at KEKB. We find BF(B+ -> p pbar pi+) = (3.06^{+0.73}_{-0.62} \pm 0.37)*10^{-6}, BF(B0 -> p pbar K0) =(1.88^{+0.77}_{-0.60} \pm 0.23)*10^{-6}, and BF(B+ -> p pbar K*+) = (10.3^{+3.6 + 1.3}_{-2.8 -1.7})*10^{-6}. We also update BF(B+ -> p pbar K+) = (5.66^{+0.67}_{-0.57} \pm 0.62)* 10^{-6}, and present an upper limit on BF(B0 …
We report on a measurement of $b$-hadron lifetimes in the fully reconstructed decay modes B^+ -->J/Psi K+, B^0 --> J/Psi K*, B^0 --> J/Psi Ks, and Lambda_b --> J/Psi Lambda using data corresponding to an integrated luminosity of 4.3 ${\rm fb}^{-1}$, collected by the CDF II detector at the Fermilab Tevatron. The measured lifetimes are $τ$B^+ = $1.639 \pm 0.009 ({\rm stat}) \pm 0.009 {\rm (syst) ~ ps}$, $τ$B^0 = $1.507 \pm 0.010 ({\rm stat}) \pm 0.008 {\rm (syst) ~ ps}$ and $τ$Lambda_b = $1.537 \pm 0.045 ({\rm stat}) \pm 0.014 {\rm (syst) ~ ps}$. The lifetime ratios are $τ$B^+/$τ$B^0 = $1.088 \p…
Observation of B0 to Lambda Lambdabar K0 and B0 to Lambda Lambdabar K*0 at Belle
We study the charmless decays B to Lambda Lambdabar h, where h stands for pi^+, K^+,K^0,K^{*+}, or K^{*0}, using a 605 fb^{-1} data sample collected at the Upsilon(4S)resonance with the Belle detector at the KEKB asymmetric energy e^+ e^- collider. We observe B0 to Lambda Lambdabar K0 and B0 to Lambda Lambdabar K*0 with branching fractions of (4.76^{+0.84}_{-0.68} (stat.) \pm 0.61 (syst.)) \times 10^{-6} and (2.46^{+0.87}_{-0.72} \pm 0.34) \times 10^{-6}, respectively. The significances of these signals in the threshold-mass enhanced mass region are 12.4 sigma and 9.3 sigma, respectively. We a…
We study charmless $B^+$ meson decays to the $p \barΛ π^+ π^-$ final state using a $605 {\rm fb}^{-1}$ data sample collected at the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. There are significant signals found with the $p\barΛ$ mass peaking near threshold. The observed branching fraction for non-resonant $ B^+ \to p \barΛ} π^+ π^-$ is $(5.92^{+0.88}_{-0.84} (stat.) \pm 0.69 (syst.)) \times 10^{-6}$ with a significance of 9.1 standard deviations. We also observe the intermediate three-body decay $B^+ \to p \barΛ ρ^0$ with a branching fraction of…
We review recent experimental results on Bd and Bs mesons decays by the BaBar and Belle experiments. These include measurements of the color-suppressed decays B0bar to D(*)0h0, h0=pi0, eta, etaprime, omega, observation of the baryonic decay B0bar to Lambdac+ Lambdabar K-, measurements of the charmless decays B to eta h, h=K, pi, B to Kpi and observation of CP eigenstates in the Bs decays: B0s to J/psi f0(980), B0s to J/psi f0(1370) and B0s to J/psi eta. The theoretical implications of these results will be considered.
The large data sample recorded with the Belle detector at the Y(5S) energy provides a unique opportunity to study the poorly-known $\bs$ meson. Two analyses, performed with a data sample representing an integrated luminosity of 121 /fb, are presented: the measurement of the Bs0->J/psi f0(980) and Bs0->J/psi f0(1370) branching fractions, and the 5sigma observation of the decay Bs0-bar->Lambda(c)+ pi- Lambda-bar which is the first observation of a baryonic Bs0 decay. In addition, we present new results of a measurement of the CKM angle phi_1(beta) with B pi tagged events.
First Measurement of the Ratio of Branching Fractions B(Lambda_b to Lambda_c mu nu)/B(Lambda_b to Lambda_c pi)
分析使用的数据从积分亮度约172 pb-1的ppbar碰撞在sqrt（s）=1.96 TeV，收集与CDF II探测器在费米实验室Tevatron。Lambda_b和B 0相对支化分数测量为：B（Lambda_b至Lambda_c+ mu nu）/B（Lambda_b至Lambda_c+ pi）= 16.6 +- 3.0（stat）+- 1.0（syst）+2.6 -3.4（PDG）+- 0.3（EBR），B（B0至D+ mu nu）/B（B 0至D+ pi）= 9.9 +- 1.0（统计）+- 0.6（系统）+- 0.4（PDG）+- 0.5（EBR），B（B0至D*+ mu nu）/B（B 0 to D*+ pi）= 16.5 +- 2.3（stat）+- 0.6（syst）+- 0.5（PDG）+- 0.8（EBR）本文还测量了四个新的λ_b半轻子衰变的分支分数：Lambda_b到Lambda_c（2595）+ mu nu，Lambda_b到Lambda_c（2625）+ mu nu，Lambda_b到Sigma_c（2455）0 pi mu nu，Lambda_b到Sigma_c（2455）++ pi mu nu，相对于Lambda_b到Lambda_c mu nu衰变的分支分数。最后，测量了p-pbar碰撞中产生的Lambda_b重子的横动量分布，发现与B_0介子的横动量…
We report results of a search for tau lepton decays strongly suppressed in the Standard Model based on the world-largest data sample accumulated with the Belle detector at the KEKB asymmetric-energy e+e- collider. The decays include: lepton flavor and lepton number violating tau decays into a lepton (e or mu) and two charged mesons (K or pi) as well as lepton and baryon number violating tau decays into a Lambda and a charged meson (K or pi). The sensitivity to the branching fractions is significantly improved compared to our previous results and reaches O(10^{-8}).
We report the results of a high-statistics search for H-dibaryon production in inclusive Y(1S) and Y(2S) decays. No indication of an H-dibaryon with mass near the M_H=2m_Lambda threshold is seen in either the H-> Lambda p pi- or Lambda-Lambda decay channels and 90% confidence level branching-fraction upper limits are set that are between one and two orders of magnitude below the measured branching fractions for inclusive Y(1S) and Y(2S) decays to antideuterons. Since Y(1,2S) decays produce flavor-SU(3)-symmetric final states, these results put stringent constraints on H-dibaryon properties. Th…
We present results of femtoscopic analysis with K0s-K0s, Kch-Kch, p-p, pbar-pbar, p-pbar and lambda-antilambda in Pb-Pb collisions at sqrt{s_NN}=2.76 TeV and K0s-K0s in pp collisions at sqrt{s}=7 TeV registered by ALICE at the LHC. The femtoscopic radius is extracted from the one-dimensional correlation functions. The analysis reveals that the emission source sizes of pions, kaons and protons measured in heavy-ion collisions exhibit approximate transverse mass scaling which is consistent with hydrodynamic collectivity prediction. Furthermore, baryon-antibaryon correlations are investigated to …
Using 121.4 fb^{-1} of data collected with the Belle detector at the Y(5S) resonance at the KEKB asymmetric-energy e^+e^- collider, we report evidence for the B_s^0 -> Lambda_c^+ Lambda-bar pi^- decay mode with a measured branching fraction (3.6 +- 1.1[stat.] {+0.3 -0.5}[syst.] +- 0.9[Lambda_c^+] +- 0.7[N_{Bs}]) * 10^{-4} and a significance of 4.4 standard deviations. This is the first evidence for a baryonic B_s^0 decay.
We present the first model-independent measurement of the absolute branching fraction of the Lambda_c+ -> p K- pi+ decay using a data sample of 978 fb^-1 collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The number of Lambda_c+ baryons is determined by reconstructing the recoiling D(*)- anti-p pi+ system in events of the type e+e- -> D(*)- anti-p pi+ Lambda_c+. The branching fraction is measured to be Br(Lambda_c+ -> p K- pi+) = (6.84 +- 0.24^{+0.21}_{-0.27})%, where the first and second uncertainties are statistical and systematic, respectively.
We report results of a study of doubly charmed baryons and charmed strange baryons. The analysis is performed using a 980 fb^-1 data sample collected with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We search for doubly charmed baryons Xi_cc^+(+) with the Lambda_c^+K^-pi^+(pi^+) and Xi_c^0pi^+(pi^+) final states. No significant signal is observed. We also search for two excited charmed strange baryons, Xi_c(3055)^+ and Xi_c(3123)^+ with the Sigma_c^++(2455)K^- and Sigma_c^++(2520)K^- final states. The Xi_c(3055)^+ signal is observed with a significance of 6.6 standard dev…
