Hadronic production of theBcmeson at TeV energies

Abstract

Based on a reliable mechanism, the cross sections of the B , hadronic production at the TeV energies of the CERN SppS, Fermilab Tevatron, CERN LHC, and SSC, as well as their possible fixed target experiments, are calculated. The results are presented numerically and indicate that the cross sections at the energies reached at the Tevatron, LHC, and SSC or higher are sufficiently large for further considering experimental studies of the B , meson at these colliders. PACS number(s1: 13.85.Ni, 12.38.Bx, 14.40.J~ The physics of the B, meson is very interesting, due to the nature of its structure. Comparing it with 77,,J/3, and v b , Y , etc., the B, meson, on one hand the same as them, is a double heavy-quark-antiquark bound state, so the QCD-inspired potential model should work well, and, on the other hand different from them, it carries flavors explicitly; thus it may decay by the weak interaction only, and has a much longer lifetime than the others [I-3,151. The B, meson (or its antiparticle) probably is the only object having the above twofold nature in the hadron world if there are only three generations of fundamental fermions as indicated by the standard model, and a very heavy top m , indicated by 140 GeV. The reason is as follows: In addition to the c 6 o r Sb bound states, of the three families a double heavy-quark-antiquark system with this feature must contain a top or top antiquark inside. However, the top quark probably would not have time to form any hadron before decaying itself: The lowest bound of the top quark mass is proved up to m , ? 91 GeV [7] now, and the top's lifetime will become shorter as the bound is increasing. It is easy to estimate that m, 2 140 GeV happens to be the case that the top quark would not have time to form any hadron before decaying itself. Therefore the B,, as well as its antiparticle, probably is the unique object having this nature. The properties of the meson B, may potentially make it become a fruitful "laboratory" for testing potential models and understanding the weak decay mechanism for heavy flavors.The reason the experimental study of B, physics has not really started yet, interesting though the physics may be, is due to the difficulty of producing the B, mesons. The difficulty may be understood by inspecting the following most possible mechanisms of the production. The first is to produce the meson B, or its antiparticle B, by the so-called fragmentation mechanism. In fact it is practically impossible by this mechanism to produce a number of the mesons, although it is very important for *Mailing address. the production of the single heavy mesons (with one heavy quark and one light quark) such as D O , Do, D', D -, D , , &, B +, B -, B O , and Po, etc. The reason is that the possibility to create a pair of heavy quarks from the vacuum (in the B, production case) is much smaller than that to create a pair of light ones (in the latter case). According to the hadron string model [4], the relative possibilities for producing quark pairs of various flavors from the v...

Hadronic production of S-wave and P-wave charmed beauty mesons via heavy quark fragmentation

“…There was a controversy in the recent literature [23,24,25,26,27] concerning about the importance of parton fragmentation in the production of the B c (B * c ) meson at hadronic colliders. The controversy arises because the Feynman diagrams responsible for theb antiquark fragmentation form a subset of the whole set of Feynman diagrams, which contribute at the order of α 4 s .…”

“…It is therefore not clear that if the production of (bc) mesons in hadronic collisions is dominated by parton fragmentation. However, detailed calculations by Chang et al [23], Slabospitsky [24], and Kolodziej et al [27] indicated that the fragmentation approach is valid for the S-wave production at the large transverse momentum region. We will discuss more about this later in the closing section.…”

“…Recently, the production of the S-wave states has also been computed at hadronic colliders like the Tevatron and the Large Hadron Collider (LHC) both by a complete O(α 4 s ) calculation [23,24,25,26,27] and by using the simpler fragmentation approach [28,29]. We note that unlike the J/ψ production in hadronic collisions in which the major contributions come from (1) g → χ cJ fragmentation followed by the decay χ cJ → J/ψ + γ [9,10,11,12], and (2) gluon fragmentation into a color-octet (cc) 3 S 1 state which subsequently evolves nonperturbatively into J/ψ [15,16], the fragmentation diagrams for producing (bc) mesons form a subset of the whole set of…”

How to search for doubly charmed baryons and tetraquarks

“…2. In hadronic production, the process gg → bb or qq → bb may be followed by gluon bremsstrahlung and splittingb →bg →bcc to yield B c (bc) mesons [8,5,56,57,58,59,60,61,62,63]. Doubly charmed baryon production may then possibly proceed via the weak decayb → ccs.…”

Hadronic production of the doubly heavy baryonΞbcat the LHC

“…The * wuxg@cqu.edu.cn dominant mechanism for the hadronic production of Ξ bc baryon is the gluon-gluon fusion mechanism via the process g + g → Ξ bc +b +c. The gluon-gluon fusion mechanism includes 36 Feynman diagrams similar to the case of the Ξ cc baryon production [9-15, 21, 22] and the B c meson production [23][24][25], all of which can be schematically represented by Fig. (1), where k 1 and k 2 are two momenta for the initial gluons, q b2 and q c4 are momenta for the two outgoingb andc, P is the momentum of Ξ bc .…”