Congeniality bounds on quark masses from nucleosynthesis

Abstract

The work of Jaffe, Jenkins and Kimchi [Phys. Rev. D79, 065014 (2009)] is revisited to see if indeed the region of congeniality found in their analysis survives further restrictions from nucleosynthesis. It is observed that much of their congenial region disappears when imposing conditions required to produce the correct and required abundances of the primordial elements as well as ensure that stars can continue to burn hydrogen nuclei to form helium as the first step in forming heavier elements in stellar nucleosynthesis. The remaining region is a very narrow slit reduced in width from around 29 MeV found by Jaffe et al. to only about 2.2 MeV in the difference of the nucleon/quark masses. Further bounds on δmq/mq seem to reduce even this narrow slit to the physical point itself.

Interpretation of Y(10750) as a tetraquark and its production mechanism

“…is induced by non-planar diagrams [11], allowing the direct production of Y b (10750) in high energy collisions. Using this, Drell-Yan [12] and prompt production cross sections [13] for Y b (10750) are presented for the LHC. We estimate the…”

“…Hadroproduction and Drell-Yan cross sections for pp → Y b (10750) → Υ(nS) π + π − at the LHC: In [13], the hadroproduction cross sections for Υ(5S) and Υ(6S) in pp(p) collisions were calculated at the Tevatron and LHC, using the NRQCD framework [20] which adopts a factorization ansatz to separate the short-and long-distance effects. This was supplemented by the subsequent decays into Υ(1S, 2S, 3S) π + π − .…”

“…Here, i and j denote a generic parton inside a proton, f a (x 1 ) and f b (x 2 ) are the parton distribution functions (PDFs), for which the CTEQ6 PDFs [21] has been used in [13], O[N ] are the long-distance matrix elements (LDMEs), N denotes all the quantum numbers of the bb pair, which is labelled in the form 2S+1 L c J (color c, spin S, orbital angular momentum L, and total angular momentum J), andσ is a partonic cross section. The leading-order partonic processes for the S-wave configurations are:…”

“…The Summing over the partonic processes shown above, and using the branching ratios from the PDG, yields the cross sections σ(pp → Υ(5S) → (Υ(nS) → µ + µ − ) π + π − ), where n = 1, 2, 3 [13].…”

“…The error estimates in the QCD production are from the variation of the central values of the CO-LDMEs and the various decay branching ratios, as discussed in Ref. [13]. Contributions from Υ(1S, 2S, 3S) are added together in the Drell-Yan production mechanism as in Ref.…”