Search for the dark photon in $B^0 \to A^{\prime} A^{\prime}$, $A^{\prime} \to e^+ e^-$, $μ^+ μ^-$, and $π^+ π^-$ decays at Belle
S. -H. Park, Y. -J. Kwon, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, P. Behera, J. Bennett, M. Bessner, V. Bhardwaj… 展开作者
S. -H. Park, Y. -J. Kwon, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, P. Behera, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, M. Campajola, L. Cao, D. Červenkov, M. -C. Chang, P. Chang, A. Chen, B. G. Cheon, K. Chilikin, H. E. Cho, K. Cho, S. -J. Cho, S. -K. Choi, Y. Choi, S. Choudhury, D. Cinabro, S. Cunliffe, S. Das, N. Dash, G. De Nardo, F. Di Capua, J. Dingfelder, Z. Doležal, T. V. Dong, S. Eidelman, D. Epifanov, D. Ferlewicz, B. G. Fulsom, R. Garg, V. Gaur, A. Garmash, A. Giri, P. Goldenzweig, Y. Guan, K. Gudkova, C. Hadjivasiliou, T. Hara, O. Hartbrich, K. Hayasaka, H. Hayashii, M. T. Hedges, M. Hernandez Villanueva, W. -S. Hou, C. -L. Hsu, K. Huang, T. Iijima, K. Inami, G. Inguglia, A. Ishikawa, R. Itoh, M. Iwasaki, Y. Iwasaki, W. W. Jacobs, I. Jaegle, E. -J. Jang, H. B. Jeon, S. Jia, Y. Jin, C. W. Joo, K. K. Joo, K. H. Kang, G. Karyan, T. Kawasaki, C. Kiesling, D. Y. Kim, K. -H. Kim, S. H. Kim, Y. -K. Kim, K. Kinoshita, P. Kodyš, T. Konno, S. Korpar, D. Kotchetkov, P. Križan, R. Kroeger, P. Krokovny, T. Kuhr, M. Kumar, K. Kumara, K. Lalwani, I. S. Lee, S. C. Lee, C. H. Li, J. Li, L. K. Li, Y. B. Li, L. Li Gioi, J. Libby, K. Lieret, Z. Liptak, D. Liventsev, T. Luo, J. MacNaughton, C. MacQueen, M. Masuda, T. Matsuda, D. Matvienko, M. Merola, F. Metzner, K. Miyabayashi, R. Mizuk, G. B. Mohanty, S. Mohanty, T. Mori, H. -G. Moser, M. Mrvar, R. Mussa, M. Nakao, Z. Natkaniec, A. Natochii, L. Nayak, M. Nayak, M. Niiyama, N. K. Nisar, S. Nishida, S. Ogawa, H. Ono, Y. Onuki, P. Oskin, P. Pakhlov, G. Pakhlova, S. Pardi, C. W. Park, H. Park, S. Patra, S. Paul, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, T. Podobnik, V. Popov, E. Prencipe, M. T. Prim, M. Ritter, M. Röhrken, A. Rostomyan, N. Rout, G. Russo, Y. Sakai, S. Sandilya, A. Sangal, L. Santelj, T. Sanuki, V. Savinov, G. Schnell, J. Schueler, C. Schwanda, Y. Seino, K. Senyo, M. E. Sevior, M. Shapkin, C. Sharma, C. P. Shen, J. -G. Shiu, A. Sokolov, E. Solovieva, S. Stanič, M. Starič, Z. S. Stottler, J. F. Strube, M. Sumihama, K. Sumisawa, T. Sumiyoshi, W. Sutcliffe, M. Takizawa, K. Tanida, F. Tenchini, M. Uchida, T. Uglov, Y. Unno, S. Uno, P. Urquijo, S. E. Vahsen, R. Van Tonder, G. Varner, K. E. Varvell, A. Vinokurova, V. Vorobyev, E. Waheed, C. H. Wang, E. Wang, M. -Z. Wang, P. Wang, M. Watanabe, S. Watanuki, S. Wehle, E. Won, X. Xu, B. D. Yabsley, W. Yan, S. B. Yang, H. Ye, J. Yelton, J. H. Yin, Y. Yusa, Z. P. Zhang, V. Zhilich, V. Zhukova, V. Zhulanov
We present a search for the dark photon $A^{\prime}$ in the $B^0 \to A^{\prime} A^{\prime}$ decays, where $A^{\prime}$ subsequently decays to $e^+ e^-$, $μ^+ μ^-$, and $π^+ π^-$. The search is performed by analyzing $772 \times 10^6$ $B\overline{B}$ events collected by the Belle detector at the KEKB $e^+ e^-$ energy-asymmetric collider at the $Υ(4S)$ resonance. No signal is found in the dark photon mass range $0.01~\mathrm{GeV}/c^2 \le m_{A^{\prime}} \le 2.62~\mathrm{GeV}/c^2$, and we set upper limits of the branching fraction of $B^0 \to A^{\prime} A^{\prime}$ at the 90\% confidence level. The products of branching fractions, $\mathcal{B}(B^0 \to A^{\prime} A^{\prime}) \times \mathcal{B}(A^{\prime} \to e^+ e^-)^2$ and $\mathcal{B}(B^0 \to A^{\prime} A^{\prime}) \times \mathcal{B}(A^{\prime} \to μ^+ μ^-)^2$, have limits of the order of $10^{-8}$ depending on the $A^{\prime}$ mass. Furthermore, considering $A^{\prime}$ decay rate to each pair of charged particles, the upper limits of $\mathcal{B}(B^0 \to A^{\prime} A^{\prime})$ are of the order of $10^{-8}$-$10^{-5}$. From the upper limits of $\mathcal{B}(B^0 \to A^{\prime} A^{\prime})$, we obtain the Higgs portal coupling for each assumed dark photon and dark Higgs mass. The Higgs portal couplings are of the order of $10^{-2}$-$10^{-1}$ at $m_{h'} \simeq m_{B^0} \pm 40~\mathrm{MeV}/c^2$ and $10^{-1}$-$1$ at $m_{h'} \simeq m_{B^0} \pm 3~\mathrm{GeV}/c^2$.
Belle II是Belle实验的重大升级，在日本的$B$工厂SuperKEKB运行。由于SuperKEKB对撞机的设计光度为8 $\;\times\;$ 10 $^{35}$ cm $^{-2}$ s $^{-1}$，大约是KEKB的40倍，Belle II的目标是在8年内收集50 ab $^{-1}$的数据。用于物理分析的第一次数据采集运行已于2018年4月开始，亮度低于用于调试目的的设计亮度。即使使用早期的数据集，具有高达20 fb $^{-1}$的积分亮度，Belle II也可以改善暗区领域的当前结果。在本文中，我们将提出预期的Belle II的不可见衰减的暗光子，类轴子粒子和不可见衰减的$Z^{\prime}$假设$L_μ-L_τ$模型的灵敏度。
在SuperKEKB能量不对称$e^+ e^-$对撞机上进行的Belle II实验是对日本KEK实验室B工厂设施的重大升级。机器的设计光度为$8\times 10^{35}$ cm $^{-2}$ s $^{-1}$，Belle II实验的目标是记录50 ab $^{-1}$的数据，比其前身多50倍。从2018年2月到7月，机器已经完成了调试运行，达到了$5.5\times 10^{33}$ cm $^{-2}$ s $^{-1}$的峰值光度，Belle II已经记录了大约0.5 fb $^{-1}$的数据样本。SuperKEKB已于二零一九年三月开始正式营运。这个早期的数据集与专门设计的触发器已经提供了在GeV质量范围内搜索各种各样的暗扇区粒子的可能性，以补充大型强子对撞机（LHC）和专用的低能实验;这些搜索将受益于积累过程中的更多数据。本次演讲将回顾Belle II的暗区搜索状况，重点关注早期数据的发现潜力，并展示第一批结果。
Searching Dark Photons using displaced vertices at Belle II -- with backgrounds
Institute for Theoretical Physics, Heidelberg University（海德堡大学理论物理研究所）；Institute for Mathematics, Astrophysics and Particle Physics, Radboud University（拉德堡德大学数学、天体物理学和粒子物理研究所）；Nikhef（荷兰国家核子和亚原子物理研究所）
Dark Matter emission at Belle II and NA62 in Minimal Flavor Violation framework
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati（意大利国家核物理研究所，弗朗卡蒂国家实验室）；Asia Pacific Center for Theoretical Physics（亚太理论物理中心）；Department of Physics, Pohang University of Science and Technology（浦项科技大学物理系）；Department of Physics, Kyushu University（九州大学物理系）；CERN, European Organization for Nuclear Research（欧洲核子研究组织（CERN））；LAPTh, Université Savoie Mont-Blanc et CNRS（萨瓦蒙布朗大学与法国国家科学研究中心联合理论物理实验室）
Charged current $b \to c τ\barν_τ$ anomalies in a general $W^\prime$ boson scenario
从Belle实验获得的最新实验信息，以及BABAR和LHCb实验积累的信息，都表明了与带电电流跃迁$b \to c τ\barν_τ$相关的$R(D)$和$R(D^{*})$比值中存在异常。尽管Belle的测量结果与标准模型（SM）的预测一致，但新的实验世界平均值仍然表现出紧张。此外，由Belle协作组观察到的与通道$B \to D^\ast τ\barν_τ$相关的$D^\ast$纵向极化$F_L(D^\ast)$和由LHCb协作组测量的比率$R(J/ψ)$也显示出与它们相应的SM估计的差异。我们提出了一个模型独立的研究的基础上，最一般的有效拉格朗日产生树级的有效贡献的过渡$b \to c τ\barν_τ$诱导的一般$W^\prime$玻色子。而不是考虑任何特定的新物理（NP）实现，我们进行了分析，考虑所有不同的手征电荷的魅力底部和$τ$ - $ν_τ$相互作用项与带电$W^\prime$玻色子解释的异常。我们提出了一个唯象的参数空间的研究允许新的实验$b \to c τ\barν_τ$数据和单tau签名$pp \to τ_h X + \rm{MET}$在大型强子对撞机。为了比较，我们包括一些$W^\prime$玻色子NP实现，已经在文献中研究。
Search for dark matter production in association with the Z$^{\prime}$ boson at the LHC in pp collisions at $\sqrt{s}$ = 8 TeV using Monte Carlo simulations
Search for the production of dark matter candidates in association with heavy dimuon resonance using the CMS open data for pp collisions at $\sqrt{s}$ = 8 TeV
