G. G. Barnaföldi

Predictions for

Predictions for charged hadron, identified light hadron, quarkonium, photon, jet and gauge bosons in p+Pb collisions at sqrt s_NN = 5 TeV are compiled and compared. When test run data are available, they are compared to the model predictions.

p+

A third workshop on small-x physics, within the Small-x Collaboration, was held in Hamburg in May 2004 with the aim of overviewing recent theoretical progress in this area and summarizing the experimental status.

Pb Collisions at sqrt s_NN = 5 TeV

Collinear factorized perturbative QCD model predictions are compared for p+Pb at 4.4A TeV to test nuclear shadowing of parton distribution at the Large Hadron Collider (LHC). The nuclear modification factor (NMF), R_{pPb}(y=0,p_T<20 GeV/c) = dn_{p Pb} /(N_{coll}(b)dn_{pp}), is computed with electron-nucleus (e+A) global fit with different nuclear shadow distributions and compared to fixed Q^2 shadow ansatz used in Monte Carlo Heavy Ion Jet Interacting Generator (HIJING) type models. Due to rapid DGLAP reduction of shadowing with increasing Q^2 used in e+A global fit, our results confirm that no significant initial state suppression is expected (R_{pPb} (p_T) = 1 \pm 0.1) in the p_T range 5 to 20 GeV/ c. In contrast, the fixed Q^2 shadowing models assumed in HIJING type models predict in the above p_T range a sizable suppression, R_{pPb} (p_T) = 0.6-0.7 at mid-pseudorapidity that is similar to the color glass condensate (CGC) model predictions. For central (N_{coll} = 12) p+ Pb collisions and at forward pseudorapidity (\eta = 6) the HIJING type models predict smaller values of nuclear modification factors (R_{pPb}(p_T)) than in minimum bias events at mid-pseudorapidity (\eta = 0). Observation of R_{pPb}(p_T= 5-20 GeV/c) less than 0.6 for minimum bias p+A collisions would pose a serious difficulty for separating initial from final state interactions in Pb+Pb collisions at LHC energies.

Small x Phenomenology - summary of the 3rd Lund Small x Workshop in 2004

Higher-order perturbative QCD corrections play an important role in the reproduction of data at high transverse momenta in the energy range 20 GeV≤(s)1/2≤200 GeV. Recent calculations of photon and pion production in pp collisions yield detailed information on the next-to-leading-order (NLO) contributions. However, the application of these results in proton-nucleus and nucleus-nucleus collisions is not straightforward. The study of nuclear effects requires a simplified understanding of the output of these computations. Here we summarize our analysis of recent calculations, aimed at handling the NLO results by introducing process and energy-dependent K factors.

Predictions for p + Pb at 4.4A TeV to test initial-state nuclear shadowing at energies available at the CERN Large Hadron Collider

We summarize new pQCD results on pion production in proton-proton (pp), proton-nucleus (pA) and nucleus-nucleus (AA) collisions. Our calculation introduces intrinsic parton transverse momentum (k T ) and is performed effectively at next-to-leading order (NLO), applying a K factor extracted for jet events. Two different factorization scales, Q = p T, jet /2 and p T, jet are used. Experimental data in pA collisions imply a preference for the latter choice at NLO level. We display our results at CERN SPS for AA collisions.

Jets and produced particles in pp collisions from SPS to RHIC energies for nuclear applications

In ultrarelativistic heavy-ion collisions, in the 2 GeV

Perturbative QCD Results on Pion Production in pp, pA and AA Collisions

<p_\perp<

Multiple scattering and pt-broadening at RHIC energies

6 GeV transverse momentum region, the soft and semi-hard multiple scattering of the incoming nucleons in the nuclear medium results in the broadening of the expected hadronic (e.g. pion)

A very high momentum particle identification detector

p_\perp

Inclusive photon production at forward rapidities in proton–proton collisions at √s = 0.9, 2.76 and 7 TeV - eScholarship

spectra relative to proton-proton (