In order to clarify the puzzling problems in double charm production, relativistic corrections at order v 2 to the processes e + e − → J/ψ + η c and e + e − → J/ψ + cc at B factories are studied in non-relativistic quantum chromodynamics. The short-distance parts of production cross sections are calculated perturbatively, while the long-distance matrix elements are estimated from J/ψ and η c decays up to errors of order v 4 . Our results show that the relativistic correction to the exclusive process e + e − → J/ψ + η c is significant, which, when combined together with the next-toleading order α s corrections, could resolve the large discrepancy between theory and experiment; whereas for the inclusive process e + e − → J/ψ + cc the relativistic correction is tiny and negligible.The physical reason for the above difference between exclusive and inclusive processes largely lies in the fact that in the exclusive process the relative momentum between quarks in charmonium substantially reduces the virtuality of the gluon that converts into a charm quark pair, but this is not the case for the inclusive process, in which the charm quark fragmentation c → J/ψ + c is significant, and QCD radiative corrections can be more essential.

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We analyze the first measurement of ηc production, performed by the LHCb Collaboration, in the nonrelativistic-QCD (NRQCD) factorization framework at next-to-leading order (NLO) in the strong-coupling constant αs and the relative velocity v of the bound quarks including the feeddown from hc mesons. Converting the long-distance matrix elements (LDMEs) extracted by various groups from J/ψ yield and polarization data to the ηc case using heavy-quark spin symmetry, we find that the resulting NLO NRQCD predictions greatly overshoot the LHCb data, while the color-singlet model provides an excellent description.PACS numbers: 12.38. Bx, 12.39.St, 13.85.Ni, 14.40.Pq Despite concerted experimental and theoretical efforts ever since the discovery of the J/ψ meson in the November revolution of 1974 (The Nobel Prize in Physics 1976), the genuine mechanism underlying the production and decay of heavy quarkonia, which are QCD bound states of a heavy quark Q = c, b and its antiparticle Q, has remained mysterious. The effective quantum field theory of nonrelativistic QCD (NRQCD) [1] endowed with an appropriate factorization theorem [2] arguably constitutes the most probable candidate theory at the present time. This implies a separation of process-dependent shortdistance coefficients (SDCs), to be calculated perturbatively as expansions in the strong-coupling constant α s , from supposedly universal long-distance matrix elements (LDMEs), to be extracted from experiment. The relative importance of the latter is subject to velocity scaling rules [3], which predict each of the LDMEs to scale with a definite power of the heavy-quark velocity v. In this way, the theoretical predictions are organized as double expansions in α s and v. A crucial feature of this formalism is that the QQ pair can at short distances be produced in any Fock state n = 2S+1 L [a] J with definite spin S, orbital angular momentum L, total angular momentum J, and color multiplicity a = 1, 8. In this way, it complements the color-singlet (CS) model (CSM), which only includes the very 2S+1 L [1] J state of the physical quarkonium, and thus cures a severe conceptual shortcoming of the latter, namely the existence of uncanceled infrared (IR) singularities beyond L = 0. However, the CSM does provide IR-finite NLO predictions for S-wave charmonia, such as the η c and J/ψ mesons considered here.Despite its theoretical rigor, NRQCD factorization has reached the crossroads in the J/ψ case. While a global fit [4] to the J/ψ yields measured in hadroproduction, photoproduction, γγ scattering, and e + e − annihilation successfully pins down the leading color-octet (CO) LDMEs,, in compliance with the velocity scaling rules, the resulting predictions for J/ψ polarization in hadroproduction are in striking disagreement with measurements at the Fermilab Tevatron and the CERN LHC [5]. Vice versa, fits to data on J/ψ yield and polarization in hadroproduction work reasonably well [6][7][8], but hopelessly fail in comparisons to the world's data from other than hadronic collis...

In the epicenter of the Lushan M S 7.0 earthquake there are several imbricate active reverse faults lying from northwest to southeast, namely the Gengda-Longdong, Yanjing-Wulong, Shuangshi-Dachuan and Dayi faults. Emergency field investigations have indicated that no apparent earthquake surface rupture zones were located along these active faults or their adjacent areas. Only brittle compressive ruptures in the cement-covered pavements can be seen in Shuangshi, Taiping, Longxing and Longmen Townships, and these ruptures show that a local crustal shortening occurred in the region during the earthquake. Combining spatial distribution of the relocated aftershocks and focal mechanism solutions, it is inferred that the Lushan earthquake is classified as a typical blind reverse-fault earthquake, and it is advised that the relevant departments should pay great attention to other historically un-ruptured segments along the Longmenshan thrust belt and throughout its adjacent areas.Lushan earthquake, earthquake surface rupture zone, blind reverse-fault earthquake, Longmenshan thrust belt, Qinghai-Tibetan Plateau Citation:Xu X W, Wen X Z, Han Z J, et al. Lushan M S 7.0 earthquake: A blind reserve-fault event.

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