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Wang, E., Xie, J. J., Geng, L. S., & Oset, E. (2019). The X(4140) and X(4160) resonances in the e(+)e(-) -> gamma J/psi phi reaction. Chin. Phys. C, 43(11), 113101–10pp.
Abstract: We investigate the J/psi phi invariant mass distribution in the e(+)e(-) -> gamma J/psi phi reaction at a center-of-mass energy of root s = 4.6 GeV measured by the BESIII collaboration, which concluded that no significant signals were observed for e(+)e(-) -> gamma J/psi phi because of the low statistics. We show, however, that the J/psi phi invariant mass distribution is compatible with the existence of the X(4140) state, appearing as a peak, and a strong cusp structure at the D-s*(D) over bar (s)* threshold, resulting from the molecular nature of the X(4160) state, which provides a substantial contribution to the reaction. This is consistent with our previous analysis of the B+ -> J psi phi K+ decay measured by the LHCb collaboration. We strongly suggest further measurements of this process with more statistics to clarify the nature of the X(4140) and X(4160) resonances.
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Cheng, L., Eberhardt, O., & Murphy, C. W. (2019). Novel theoretical constraints for color-octet scalar models. Chin. Phys. C, 43(9), 093101–11pp.
Abstract: We study the theoretical constraints on a model whose scalar sector contains one color octet and one or two color singlet SU(2)(L) doublets. To ensure unitarity of the theory, we constrain the parameters of the scalar potential for the first time at the next-to-leading order in perturbation theory. Moreover, we derive new conditions guaranteeing the stability of the potential. We employ the HEPfit package to extract viable parameter regions at the electroweak scale and test the stability of the renormalization group evolution up to the multi-TeV region. Furthermore, we set upper limits on the scalar mass splittings. All results are given for both cases with and without a second scalar color singlet.
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Wang, Y. F., Yao, D. L., & Zheng, H. Q. (2019). New insights on low energy pi N scattering amplitudes: comprehensive analyses at O (p(3)) level. Chin. Phys. C, 43(6), 064110–22pp.
Abstract: A production representation of partial-wave S matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated using the O (p(3)) results obtained in covariant baryon chiral perturbation theory within the extendedon-nass-shell scheme. By fitting to data on partial-wave phase shifts, it is indicated that the existences of hidden poles in S-11 and P-11 channels, as conjectured in our previous paper [Eur. Phys. J. C, 78(7): 543 (2018)], are firmly established. Specifically, the pole mass of the S-11 hidden resonance is determined to be (895 +/- 81)-(164 +/- 23)i MeV, whereas, the virtual pole in the P-11 channel locates at (966 +/- 18) MeV. It is found that analyses at the O (p(3)) level improves significantly the fit quality, comparing with the previous O (p(2)) one. Quantitative studies with cautious physical discussions are also conducted for the other S- and P-wave channels.
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Centelles Chulia, S., Cepedello, R., Peinado, E., & Srivastava, R. (2020). Scotogenic dark symmetry as a residual subgroup of Standard Model symmetries. Chin. Phys. C, 44(8), 083110–7pp.
Abstract: We demonstrate that a scotogenic dark symmetry can be obtained as a residual subgroup of the global U(1)(B-L) symmetry already present in the Standard Model. In addition, we propose a general framework in which the U(1)(B-L) symmetry is spontaneously broken into an even Z(2n) subgroup, setting the general conditions for neutrinos to be Majorana and for dark matter stability to exist in terms of the residual Z(2n). As an example, under this general framework, we build a class of simple models where, in a scotogenic manner, the dark matter candidate is the lightest particle running inside the mass loop of a neutrino. The global U(1)(B-L) symmetry in our framework, being anomaly free, can also be gauged in a straightforward manner leading to a richer phenomenology.
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Belle II Collaboration(Abudinen, F. et al), Gomis, P., & Marinas, C. (2020). Measurement of the integrated luminosity of the Phase 2 data of the Belle II experiment. Chin. Phys. C, 44(2), 021001–12pp.
Abstract: From April to July 2018, a data sample at the peak energy of the resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be (, where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II.
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