Chinese Physics C

QCD analysis of CMS W + charm measurements at LHC with ${\sqrt { s} = 7\; {\bf{TeV}}}$ and implications for strange PDF

Nijat Yalkun, Sayipjamal Dulat

2019, 43(12): 123101. doi: 10.1088/1674-1137/43/12/123101

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Abstract:
We calculate cross-sections and cross-section ratios of a charm quark production in association with a W gauge boson at next-to-leading order QCD using MadGraph and CT10NNLO, CT14NNLO, and MSTW2008NNLO PDFs. We compare the results with measurements from the CMS detector at the LHC at a center-of-mass energy of 7 TeV. Moreover, we calculate absolute and normalized differential cross-sections as well as differential cross-section ratios as a function of the lepton pseudorapidity from the W boson decay. The correlation between the CT14NNLO PDFs and predictions for

\begin{document}$W+$\end{document}

charm data are studied as well. Furthermore, by employing the error PDF updating method proposed by the CTEQ-TEA group, we update CT14NNLO PDFs, and analyze the impact of CMS 7 TeV

\begin{document}$W+$\end{document}

charm production data to the original CT14NNLO PDFs. By comparison of the

\begin{document}$g(x,Q)$\end{document}

,

\begin{document}$s(x,Q)$\end{document}

,

\begin{document}$u(x,Q)$\end{document}

,

\begin{document}$d(x,Q)$\end{document}

,

\begin{document}$\bar u(x,Q)$\end{document}

, and

\begin{document}$\bar d(x,Q)$\end{document}

PDFs at

\begin{document}$Q=1.3$\end{document}

GeV and

\begin{document}$Q = 100$\end{document}

GeV for the CT14NNLO and CT14NNLO+Wc, we see that the error band of the

\begin{document}$s(x,Q)$\end{document}

PDF is reduced in the region

\begin{document}$x<0.4$\end{document}

, and the error band of

\begin{document}$g(x,Q)$\end{document}

PDF is also slightly reduced at region

\begin{document}$0.01 < x<0.1$\end{document}

.

Vector hidden-bottom tetraquark candidate: Y(10750)

Zhi-Gang Wang

2019, 43(12): 123102. doi: 10.1088/1674-1137/43/12/123102

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Abstract:
In this article, we take the scalar diquark and antidiquark operators as the basic constituents, and construct the

\begin{document}$C\gamma_5\otimes\stackrel{\leftrightarrow}{\partial}_\mu\otimes \gamma_5C$\end{document}

type tetraquark current to study Y(10750) with the QCD sum rules. The predicted mass

\begin{document}$M_{Y}=10.75\pm0.10\,\rm{GeV}$\end{document}

and width

\begin{document}$\Gamma_Y= 33.60^{+16.64}_{-9.45}\,{\rm{MeV}}$\end{document}

support the assignment of Y(10750) as the diquark-antidiquark type vector hidden-bottom tetraquark state, with a relative P-wave between the diquark and antidiquark constituents.

Precision study of ${ {W^-W^+H}}$ production including parton shower effects at CERN Large Hadron Collider

Huan-Yu Bi, Ren-You Zhang, Wen-Gan Ma, Yi Jiang, Xiao-Zhou Li, Peng-Fei Duan

2019, 43(12): 123103. doi: 10.1088/1674-1137/43/12/123103

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Abstract:
The precision study of

\begin{document}$W^-W^+H$\end{document}

production with subsequent

\begin{document}$W^{\pm} \rightarrow l^{\pm} \overset{ _{(-)}}{\nu_{l}}$\end{document}

and

\begin{document}$H \rightarrow b\bar{b}$\end{document}

decays at the Large Hadron Collider (LHC) aids in the investigation of Higgs gauge couplings and the search for new physics beyond the standard model. In this study, we calculate the shower-matched next-to-leading order QCD and electroweak (EW) corrections from the

\begin{document}$q\bar{q}$\end{document}

annihilation and photon-induced channels to the

\begin{document}$W^-W^+H$\end{document}

production at the

\begin{document}$14~ {\rm TeV}$\end{document}

LHC. We deal with the subsequent decays of Higgs and

\begin{document}$W^{\pm}$\end{document}

bosons by adopting the MADSPIN method. Both the integrated cross section and some kinematic distributions of

\begin{document}$W^{\pm}$\end{document}

, H, and their decay products are provided. We find that the QCD correction significantly enhances the leading-order differential cross section, while the EW correction from the

\begin{document}$q\bar{q}$\end{document}

annihilation channel obviously suppresses it, especially in the high energy phase-space region, due to the Sudakov effect. The

\begin{document}$q\gamma$\end{document}

- and

\begin{document}$\gamma\gamma$\end{document}

-induced relative corrections are positive and insensitive to the transverse momenta of

\begin{document}$W^{\pm}$\end{document}

, H, and their decay products. These photon-induced corrections compensate the negative

\begin{document}$q\bar{q}$\end{document}

-initiated EW correction, and become the dominant EW contribution as the increment of the

\begin{document}$pp$\end{document}

colliding energy. The parton shower (PS) effects on kinematic distributions are not negligible. The relative PS correction to the b-jet transverse momentum distribution can exceed 100% in the high

\begin{document}$p_{T, b}$\end{document}

region. Moreover, we investigate the scale and PDF uncertainties, and find that the theoretical error of the

\begin{document}${\rm QCD}+{\rm EW}+q\gamma+\gamma\gamma$\end{document}

-corrected integrated cross section mainly originates from the renormalization scale dependence of the QCD correction.

Recalibration of the binding energy of hypernuclei measured in emulsion experiments and its implications

Peng Liu, Jinhui Chen, Declan Keane, Zhangbu Xu, Yu-Gang Ma

2019, 43(12): 124001. doi: 10.1088/1674-1137/43/12/124001

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Abstract:
The

\begin{document}$ \Lambda $\end{document}

separation energy for

\begin{document}$ \Lambda $\end{document}

hypernuclei, denoted

\begin{document}$ B_\Lambda $\end{document}

, measured in 1967, 1968, and 1973 are recalibrated using the current best estimates of the mass of particles and nuclei. The recalibrated

\begin{document}$ B_\Lambda $\end{document}

are systematically larger (except in the case of

\begin{document}$ ^6_\Lambda $\end{document}

He) than the originally published values by about 100 keV. The effect of this level of recalibration is very important for light hypernuclei, especially for the hypertriton. The early

\begin{document}$ B_\Lambda $\end{document}

values measured in 1967, 1968, and 1973 are widely used in theoretical research, and the new results provide better constraints for the conclusions of such studies.

Measurements of differential and angle-integrated cross sections for the ¹⁰B(n, α)⁷Li reaction in the neutron energy range from 1.0 eV to 2.5 MeV

Haoyu Jiang, Wei Jiang, Huaiyong Bai, Zengqi Cui, Guohui Zhang, Ruirui Fan, Han Yi, Changjun Ning, Liang Zhou, Jingyu Tang, Qi An, Jie Bao, Yu Bao, Ping Cao, Haolei Chen, Qiping Chen, Yonghao Chen, Yukai Chen, Zhen Chen, Changqing Feng, Keqing Gao, Minhao Gu, Changcai Han, Zijie Han, Guozhu He, Yongcheng He, Yang Hong, Hanxiong Huang, Weiling Huang, Xiru Huang, Xiaolu Ji, Xuyang Ji, Zhijie Jiang, Hantao Jing, Ling Kang, Mingtao Kang, Bo Li, Chao Li, Jiawen Li, Lun Li, Qiang Li, Xiao Li, Yang Li, Rong Liu, Shubin Liu, Xingyan Liu, Guangyuan Luan, Qili Mu, Binbin Qi, Jie Ren, Zhizhou Ren, Xichao Ruan, Zhaohui Song, Yingpeng Song, Hong Sun, Kang Sun, Xiaoyang Sun, Zhijia Sun, Zhixin Tan, Hongqing Tang, Xinyi Tang, Binbin Tian, Lijiao Wang, Pengcheng Wang, Qi Wang, Taofeng Wang, Zhaohui Wang, Jie Wen, Zhongwei Wen, Qingbiao Wu, Xiaoguang Wu, Xuan Wu, Likun Xie, Yiwei Yang, Li Yu, Tao Yu, Yongji Yu, Linhao Zhang, Qiwei Zhang, Xianpeng Zhang, Yuliang Zhang, Zhiyong Zhang, Yubin Zhao, Luping Zhou, Zuying Zhou, Danya

2019, 43(12): 124002. doi: 10.1088/1674-1137/43/12/124002

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Abstract:
Differential and angle-integrated cross sections for the ¹⁰B(n, α)⁷Li, ¹⁰B(n, α₀) ⁷Li and ¹⁰B(n, α₁) ⁷Li^* reactions have been measured at CSNS Back-n white neutron source. Two enriched (90%) ¹⁰B samples 5.0 cm in diameter and ~85.0 μg/cm² in thickness each with an aluminum backing were prepared, and back-to-back mounted at the sample holder. The charged particles were detected using the silicon-detector array of the Light-charged Particle Detector Array (LPDA) system. The neutron energy E_n was determined by TOF (time-of-flight) method, and the valid α events were extracted from the E_n-Amplitude two-dimensional spectrum. With 15 silicon detectors, the differential cross sections of α-particles were measured from 19.2° to 160.8°. Fitted with the Legendre polynomial series, the (n, α) cross sections were obtained through integration. The absolute cross sections were normalized using the standard cross sections of the ¹⁰B(n, α)⁷Li reaction in the 0.3 − 0.5 MeV neutron energy region. The measurement neutron energy range for the ¹⁰B(n, α)⁷Li reaction is 1.0 eV≤E_n < 2.5 MeV (67 energy points), and that for the ¹⁰B(n, α₀) ⁷Li and ¹⁰B(n, α₁) ⁷Li^* reactions is 1.0 eV ≤ E_n < 1.0 MeV (59 energy points). The present results have been analyzed by the resonance reaction mechanism and the level structure of the ¹¹B compound system, and compared with existing measurements and evaluations.

Thermal production of charmonia in Pb-Pb collisions at ${ \sqrt{{ s}_{\bf{ {\rm NN}}}}{\bf {=5.02}}}$ TeV

Baoyi Chen

2019, 43(12): 124101. doi: 10.1088/1674-1137/43/12/124101

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Abstract:
This work uses the Boltzmann transport model to study the thermal production of

\begin{document}$J/\psi$\end{document}

and