Abstract
Invariant inclusive single-particle/jet cross sections in p–p collisions can be factorized in terms of two separable pT dependences, a [pT−s] sector and an [xR−pT−s] sector. Here, we extend our earlier work by analyzing more extensive data to explore various s-dependent attributes and other systematics of inclusive jet, photon and single particle reactions. Approximate power laws in s, pT and xR are found. Physical arguments are given which relate observations to the underlying physics of parton–parton hard scattering and the parton distribution functions in the proton. We show that the A(s,pT) function, introduced in our earlier publication to describe the pT dependence of the inclusive cross section, is directly related to the underlying hard parton–parton scattering for jet production, with little influence from soft physics. In addition to the a function, we introduce another function, the F(s,xR) function that obeys radial scaling for inclusive jets and offers another test of the underlying parton physics. An application to heavy ion physics is given, where we use our variables to determine the transparency of cold nuclear matter to penetrating heavy mesons through the lead nucleus.
Highlights
Inclusive jet, direct photon and he√avy meson cross section measurements in p–p collisions at the multi-TeV energies, up to s = 13 TeV of the Large Hadron Collider (LHC), afford incisive tests of the standard model
The√overall jet production is dominated by gluon–gluon elastic scattering with that process at s = 13 TeV making up 66% of the total inclusive jet cross section in our Toy Monte Carlo simulations (MC) simulations
For a first look at the utility of our variables when applied to heavy ion (HI) collisions, we have studied the pT dependence of the a function for high transverse momentum jets in p–Pb collisions and find that it is consistent with the a function of p–p collisions, whereas the nxR behaviors of the two√types of collisions are quite different as noted in an analysis of ATLAS jets in p–Pb data at s = 5.02 TeV in our earlier publication [9]
Summary
The cross sections are frequently presented as functions of the transverse momentum pT and rapidity y defined by y = ln((E + pz)/(E − pz))/2, with E being the particle/jet total energy and pz being the component of the 3-momentum along the incoming proton direction in the p–p center of momentum (COM). Over the years, both the data and the agreement of data with Monte Carlo simulations (MC) have steadily improved as higher statistics are accumulated, better fits to the parton distributions and higher-order quantum chromodynamics (QCD) terms are considered. We demonstrate that the modified momentum factor, Λ, for meson/baryon production is directly related to the mass of the produced meson/baryon and that the underlying pT distribution is a power law in the modified transverse momentum, PT
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