The phenomenology of central exclusive production at hadron colliders

Abstract

Central exclusive production (CEP) processes in high-energy hadron-hadron collisions provide an especially clean environment in which to measure the nature and quantum numbers (in particular, the spin and parity) of new resonance states. Encouraged by the broad agreement between experimental measurements and theoretical predictions based on the Durham approach, we perform a detailed phenomenological analysis of γγ and meson pair CEP final states, paying particular attention to the theoretical uncertainties in the predictions, including those from parton distribution functions, higher-order perturbative corrections, and non-perturbative and proton dissociation contributions. We present quantitative cross-section predictions for these CEP final states at the RHIC, Tevatron and LHC colliders.

Searching for Axionlike Particles with Ultraperipheral Heavy-Ion Collisions

“…For p-p collisions, this process has been calculated [31][32][33] and constrained experimentally at 7 TeV with CMS [25]. To the best of our knowledge, no prediction is currently available for the analogous process in heavy-ion collisions.…”

Modelling exclusive meson pair production at hadron colliders

“…However, the study of meson pair CEP in fact has a long history, which far predates this approach [10][11][12][13] (see also [14][15][16] for references and recent studies). In these cases, the production process was instead considered within the framework of Regge theory (see for example [17] for an introduction), with the meson pair produced by the exchange of two Pomerons in the t-channel, as shown in Fig.…”

“…Such a 'non-perturbative' picture should be relevant at lower values of the meson transverse momentum k ⊥ , where the cross sections are largest, and may be particularly important for the case of flavour-non-singlet mesons (ππ, K K , ...), for which the perturbative contribution is expected to be dynamically suppressed; see [4]. At lower meson invariant masses M X 2 GeV there will also in general be a host of different resonances which lie on top of, and interfere with, this continuum contribution; the production of lower mass resonances was recently examined in for example [18], while in [14] the continuum background to the production of the higher-mass χ c(0,2) states via two-body π + π − , K + K − decays was considered. Moreover, we may expect data on the CEP of meson pairs to be forthcoming from CMS [19], CMS+Totem [20][21][22], ATLAS+ALFA [23,24], RHIC [25], and LHCb [26], while the results of the new analysis of the CDF data at √ s = 900 and 1960 GeV have been presented in [27,28].…”

Exclusive MSSM Higgs production at the LHC after run I

“…Also taking a more appropriate factorization scale M (rather than ≈ 0.62M) in calculating Sudakov suppression almost halves the CEP cross section (of both, the signal and background) [73]. On the other hand as discussed in [79,80] we may expect the cross section to be increased by higher order corrections and by using the CTEQ6L [81] LO proton PDF that give the best agreement of the CEP calculations with CDF data on the exclusive γγ production [82]. A combined effect of all changes is estimated to be rather small.…”