The cross section of the e+e−→Λc+Λ¯c− process is measured with unprecedented precision using data collected with the BESIII detector at /¯s=4574.5, 4580.0, 4590.0 and 4599.5 MeV. The nonzero cross ...section near the Λc+Λ¯c− production threshold is cleared. At center-of-mass energies /¯s=4574.5 and 4599.5 MeV, the higher statistics data enable us to measure the Λc polar angle distributions. From these, the Λc electric over magnetic form-factor ratios (|GE/GM|) are measured for the first time. They are found to be 1.14±0.14±0.07 and 1.23±0.05±0.03, respectively, where the first uncertainties are statistical and the second are systematic.
Here, in an analysis of a 2.92 fb–1 data sample taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions to be B(D0 → K–e+νe) = ...(3.505 ± 0.014 ± 0.033)% and B(D0 → π–e+νe) = (0.295 ± 0.004 ± 0.003)%. From a study of the differential decay rates we obtain the products of hadronic form factor and the magnitude of the CKM matrix element $f$ $^{K}_{+}$(0)|Vcs| = 0.7172 ± 0.0025 ± 0.0035 and $f$ $^{π}_{+}$(0)|Vcd| = 0.1435 ± 0.0018 ± 0.0009.
The process e+e- → Λ Λ ¯ is studied using data samples at √s = 2.2324, 2.400, 2.800 and 3.080 GeV collected with the BESIII detector operating at the BEPCII collider. The Born cross section is ...measured at √s=2.2324 GeV, which is 1.0 MeV above the Λ Λ ¯ mass threshold, to be 305±$45_{-36}^{+66}$ pb, where the first uncertainty is statistical and the second systematic. The substantial cross section near threshold is significantly larger than that expected from theory, which predicts the cross section to vanish at threshold. The Born cross sections at √s=2.400, 2.800 and 3.080 GeV are measured and found to be consistent with previous experimental results, but with improved precision. Finally, the corresponding effective electromagnetic form factors of Λ are deduced.
Observation of X in [Formula omitted] Ablikim, M; Achasov, M. N; Adlarson, P ...
The European physical journal. C, Particles and fields,
08/2020, Letnik:
80, Številka:
8
Journal Article
Recenzirano
Using a sample of Formula omitted events collected with the BESIII detector, we perform a study of Formula omitted. X(2370) is observed in the Formula omitted invariant-mass distribution with a ...statistical significance of Formula omitted. Its resonance parameters are measured to be Formula omitted and Formula omitted. The product branching fractions for Formula omitted and Formula omitted are determined to be Formula omitted and Formula omitted, respectively. No evident signal for X(2120) is observed in the Formula omitted invariant-mass distribution. The upper limits for the product branching fractions of Formula omitted and Formula omitted are determined to be Formula omitted and Formula omitted at the 90% confidence level, respectively.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We report the first measurement of the absolute branching fraction of the inclusive decay Formula omitted. The analysis is performed using an Formula omitted collision data sample corresponding to an ...integrated luminosity of 567 Formula omitted taken at Formula omitted = 4.6 GeV with the BESIII detector. Using eleven Cabibbo-favored Formula omitted decay modes and the double-tag technique, this absolute branching fraction is measured to be Formula omitted, where the first uncertainty is statistical and the second systematic. The relative deviation between the branching fractions for the inclusive decay and the observed exclusive decays is Formula omitted, which indicates that there may be some unobserved decay modes with a neutron or excited baryons in the final state.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Using a data sample corresponding to an integrated luminosity of 2.93 fb−1 taken at a center-of-mass energy of 3.773 GeV with the BESIII detector operated at the BEPCII collider, we perform an ...analysis of the semileptonic decays D0(+)→π−(0)μ+νμ. The branching fractions of D0→π−μ+νμ and D+→π0μ+νμ are measured to be (0.272±0.008stat±0.006syst)% and (0.350±0.011stat±0.010syst)%, respectively, where the former is of much improved precision compared to previous results and the latter is determined for the first time. Using these results along with previous BESIII measurements of D0(+)→π−(0)e+νe, we calculate the branching fraction ratios to be R0≡BD0→π−μ+νμ/BD0→π−e+νe=0.922±0.030stat±0.022syst and R+≡BD+→π0μ+νμ/BD+→π0e+νe=0.964±0.037stat±0.026syst, which are compatible with the theoretical expectation of lepton flavor universality within 1.7σ and 0.5σ, respectively. We also examine the branching fraction ratios in different four-momentum transfer square regions, and find no significant deviations from the standard model predictions.
Cross sections of the process e+e− → π0 π0 J / ψ at center-of-mass energies between 3.808 and 4.600 GeV are measured with high precision by using 12.4 fb−1 of data samples collected with the BESIII ...detector operating at the BEPCII collider facility. A fit to the measured energy-dependent cross sections confirms the existence of the charmoniumlike state Y ( 4220 ) . The mass and width of the Y ( 4220 ) are determined to be ( 4220.4 ± 2.4 ± 2.3 ) MeV / c2 and ( 46.2 ± 4.7 ± 2.1 ) MeV , respectively, where the first uncertainties are statistical and the second systematic. The mass and width are consistent with those measured in the process e+e− → π+π− J / ψ. The neutral charmonium-like state Zc ( 3900 )0 is observed prominently in the π 0 J / ψ invariant-mass spectrum, and, for the first time, an amplitude analysis is performed to study its properties. The spin-parity of Zc ( 3900 )0 is determined to be JP = 1+, and the pole position is ( 3893.1 ± 2.2 ± 3.0 ) − i ( 22.2 ± 2.6 ± 7.0 ) MeV / c2, which is consistent with previous studies of electrically charged Zc ( 3900 )±. In addition, cross sections of e+e− → π0Zc ( 3900 )0 → π0π0 J / ψ are extracted, and the corresponding line shape is found to agree with that of the Y ( 4220 ).
Determination of the number of J/ψ events with J/ψ → inclusive decays 麦迪娜 M. N. Achasov D. J. Ambrose 安芬芬 安琪 安正华 白景芝 班勇 J. Becker N. Berger M. Bertani 边渐鸣 E. Boger O. Bondarenko I. Boyko R. A. Briere V. Bytev 蔡啸 A. Calcaterra 曹国富 常劲帆 G. Chelkov 陈刚 陈和生 陈江川 陈玛丽 陈申见 陈晔 陈元柏 程和平 初元萍 D. Cronin-Hennessy 代洪亮 代建平 D. Dedovich 邓子艳 A. Denig I. Denysenko M. Destefanis 丁伟民 丁勇 董燎原 董明义 杜书先 方建 房双世 L. Fava F. Feldbauer 封常青 R. B. Ferroli 傅成栋 傅金林 高原宁 耿聪 K. Goetzen 龚文煊 W. Gradl M. Greco 顾旻皓 顾运厅 管颖慧 郭爱强 郭立波 郭玉萍 韩艳良 郝喜庆 F. A. Harris 何康林 何苗 何振亚 T. Held 衡月昆 侯治龙 胡海明 胡继峰 胡涛 黄彬 黄光明 黄金书 黄性涛 黄燕萍 T. Hussain 姬长胜 纪全 季晓斌 季筱璐 贾卢魁 姜丽丽 江晓山 焦健斌 焦铮 金大鹏 金山 景繁凡 N. Kalantar-Nayestanaki M. Kavatsyuk W. Kuehn 赖蔚 J. S. Lange 潘振声 李春花 李澄 李翠 36李德民 李飞 李刚 李海波 李家才 李康 李蕾 李宁博 李秋菊 李绍莉 李卫东 李卫国 李晓玲 李小男 李学潜 李秀荣 李志兵 梁昊 梁勇飞 梁羽铁 廖广瑞 廖小涛 刘北江 C. L. Liu 刘春秀 刘春燕 刘福虎 刘芳 刘峰 刘虎 刘宏邦 刘汇慧 刘怀民 刘红薇 刘觉平 刘魁勇 刘凯 刘坤 刘佩莲 刘树彬 刘翔 刘晓海 刘勇 刘豫斌 刘振安 刘志强 刘智青 H. Loehner 鲁公儒 吕海江 吕军光 吕绮雯 吕晓睿 卢云鹏 罗成林 罗民兴 罗涛 罗小兰 吕蒙 马长利 马凤才 马海龙 马秋梅 马斯 马天 马晓妍 Y. Ma F. E. Maas M. Maggiora Q. A. Malik 毛虎 冒亚军 毛泽普 J. G. Messchendorp 闵建 闵天觉 R. E. Mitchell 莫晓虎 C. Morales Morales C. Motzko N. Yu. Muchnoi Y. Nefedov 宁洁 I. B. Nikolaev 宁哲 马鹏 欧阳群 S. Pacetti 卞正烷 M. Pelizaeus 彭海平 K. Peters 平加伦 平荣刚 R. Poling E. Prencipe C. S. J. Pun 祁鸣 钱森 乔从丰 秦小帅 秦瑶 秦中华 邱进发 K. H. Rashid 荣刚 阮向东 A. Sarantsev B. D. Schaefer J. Schulze 邵明 沈成平 沈肖雁 盛华义 M. R. Shepherd 宋新颖 S. Spataro B. Spruck 孙德辉 26孙功星 孙俊峰 孙胜森 孙晓东 孙勇杰 孙永昭 孙志嘉 孙振田 唐昌建 唐晓 E. H. Thorndike 田浩来 D. Toth M. Ullrich G. S. Varner 王斌 王博群 王科 王亮亮 王灵淑 王萌 王平 王佩良 王强 王庆娟 王思广 王雄飞 汪晓莲 王雅迪 王贻芳 王亚乾 王铮 王志刚 王至勇 魏代会 P. Weidenkaff 文群刚 文硕频 M. Werner U. Wiedner 伍灵慧 吴宁 吴硕星 吴蔚 吴智 夏力钢 肖振军 谢宇广 修青磊 许国发 徐光明 徐昊 徐庆君 徐新平 徐晔 许志蕊 薛飞 薛镇 严亮 鄢文标 颜永红 杨洪勋 杨涛 杨迎 杨永栩 叶桦 叶梅 叶铭汉 俞伯祥 喻纯旭 俞洁晟 于帅鹏 苑长征 袁文龙 袁野 A. A. Zafar A. Zallo 曾云 张丙新 张炳云 张长春 张达华 张宏浩 章红宇 张杰 张金国 张敬庆 张家文 张建勇 张景芝 张雷 张书华 张太锐 张晓杰 张学尧 张瑶 张银鸿 张艳硕 张子平 张振宇 赵光 赵海升 赵京伟 赵凯旋 赵雷 赵玲 赵明刚 赵强 赵书俊 赵天池 赵祥虎 赵豫斌 赵政国 A. Zhemchugov 郑建平 郑阳恒 郑志鹏 钟彬 J. Zhong 周莉 周晓康 周小蓉 朱程 朱凯 朱科军 朱世海 朱相雷 朱兴旺 朱亚敏 朱永生 朱自安 庄建 邹冰松 邹佳恒 左嘉旭
Chinese physics C,
10/2012, Letnik:
36, Številka:
10
Journal Article
Recenzirano
Odprti dostop
The number of J/ψ events collected with the BES detector at the BEPC from June 12 to July 28, 2009 is determined to be (225.3 ± 2.8) × 10^ 6 using J/ψ→inclusive events, where the uncertainty is the ...systematic error and the statistical one is negligible.
Using a total of 9.0 fb−1 of e+e− collision data with center-of-mass energies between 4.15 and 4.30 GeV collected by the BESIII detector, we search for the processes e+e−→γX(3872) with X(3872)→π0χcJ ...for J=0, 1, 2. We report the first observation of X(3872)→π0χc1, a new decay mode of the X(3872), with a statistical significance of more than 5σ for all systematic fit variations. Normalizing to the previously established process e+e−→γX(3872) with X(3872)→π+π−J/ψ, we find B(X(3872)→π0χc1)/B(X(3872)→π+π−J/ψ)=0.88−0.27+0.33±0.10, where the first error is statistical and the second is systematic. We set 90% confidence level upper limits on the corresponding ratios for the decays to π0χc0 and π0χc2 of 19 and 1.1, respectively.