nuclear modifications in saturated glauber model from sps to lhc energies
DESCRIPTION
Nuclear Modifications in Saturated Glauber Model from SPS to LHC Energies. Szilveszter Miklós Harangozó Zimányi Winter School 2013. Supervisor: Dr. Gergely Gábor Barnaföldi Wigner RCP of the HAS Department of Particle & Nuclear Physics. Consultant: Dr . Gábor Papp ELTE – TTK - PowerPoint PPT PresentationTRANSCRIPT
Nuclear Modifications in Saturated Glauber Model from SPS to LHC Energies
Szilveszter Miklós HarangozóZimányi Winter School 2013
Consultant: Dr. Gábor Papp
ELTE – TTKDepartment of Theoretical
Physics
Supervisor:Dr. Gergely Gábor BarnaföldiWigner RCP of the HASDepartment of Particle & Nuclear Physics
pQCD based parton model
• Nucleon-Nucleon reactions
• Factorization: we assume, the process can be factorized into 3 independent phase
pQCD based parton model
• We calculate the cross sections with a convolution described above.
• We characterize the PDFs & FFs as probability density functions, which can not be calculated perturbatively.
Parton Distribution Function (PDF)
hard partonic scattering
Fragmentation Function (FF)
Improving the model
• 40% uncertanity is too much.
• Phenomenological input.
• Parton’s transverse (intrinsic) momenta have been taken into account.
Assume: transverse momentum distribution is Gaussian:
The c.m. energy dependence of
• Comparison of experimental spectra and results of the calculations
• Uncertanities come from the Principle of Minimal Sensitivity
• The model is more sensitive at low pT-s for the parameter
• Take a look at the tendency…
The pT & dependence of
• best fit for every pT value• for a fixed , pT independent
values can be assumed
• best fit for the average pT• intrinsic transverse
momentum seems to decrease
pT dependence of the dependence of the
Good pp reference spectra can be obtained
Proton-Nucleus (pA) collision
• Experience: the yield differs from the expected: atomic number (A) times the one from pp spectra
• Measuring tool: Nuclear Modification Factor (NMF), RpA
• Difference: Nuclear Effectswhere is the number of binary collisions
Nuclear Effects
Nuclear Effects
Nuclear Effects
Multiple Scattering
Nuclear Modifications of PDF’s
• Classic and Saturated Glauber model
• Dependence on the impact parameter, b
• Intrinsic transverse momentum distribution broadens:
• Suppression of the yield at low pT-s
• Several parameterizations has been implemented by different groups
Parameters for the saturated Glauber model in pA collisions
Search for the universal Csat constantMaximum 3-4 collision with CSat ≈ 0.35
Cronin-effect in the saturated Glauber model
Dependency of the Cronin-peak’s maximum against the Atomic number
• ν: number of semihard collisions
• parameters fitted for experiments
• at fixed , peak stays put
Cronin-effect in the saturated Glauber model
Dependency of the Cronin-peak’s maximum against the Atomic number
• shadowing and saturation also suppresses the spectra
• in fully saturated case we get the original dependency
• we can apply a correction to the formula:
The kTpQCD v2.0 code
PDFFFpQCD
The kTpQCD v2.0 code
• Several parameterization can be probed within the same framework
• Original codes has been implemented
• Easy to add new type of PDFs, FFs, etc.
Pro.:
The kTpQCD v2.1 code
eps09s.cpp
Example: New shadowing: EPS09s
Ref.: 10.1007/JHEP07(2012)073
Reconstruction
• HIJING shadowing + Multiple scattering
• EPS09s shadowing
• Both parameterizations gives acceptable results
• For HIJING ν= 4 gives the best fit
• For RHIC results EPS09s is the best
Questions - Motivation
• Which nuclear effects cause the peripheral anomalies?
• Can we model model them?
• To claim a better understand of the Glauber-model
• Find the limits (or a better implementation) of the saturated picture
Summary
• pp reference
• first results on minimum bias collisions
• an updated code with “easy-to-upgrade” properties
We have:
We don’t have: • good enough parameterization for LHC energies
• better understand of the peripheral collisions
• an updated code with “easy-to-upgrade” properties
Thank you for your consideration!