QM08 J. Schukraft1
What What elseelse can one do with can one do with pp@LHC ?pp@LHC ?
pp at LHC: plenty of everything.. Lots of energy: 14 TeV Lots of time: several months/year LotsLots of rate : L: 1030 - 1034cm-2s-1 => MinBias rate > 50 kHz– 500 MHz
Physics: The usual suspects.. SM, BSM: Higgs, Susy, black holes, ….. nonpert QCD: low x physics, Color Glass, baryon transport, …. heavy ion: comparison data (necessary, but boring ?)
A new suspect at LHC: light ion physics with protons ?
QM08 J. Schukraft2
Global pp event propertiesGlobal pp event properties Multiplicity distribution at LHC
quite respectable particle densities dNch/d ~ 50 – 100 can be reached ! > central S+S @ SPS, mid-central Cu-Cu @ RHIC
naïvely, energy density > 5 – 10 GeV/fm3
0 = 1 fm, V = 5 fm3
even protons get obese these days p@LHC ~ small (but very dense) nucleus@SPS
‘QGP’ physics with protons at least: onset of hadronic FS interactions maybe: collective hadronic/partonic dynamics why not: the QGP, mini serving
60,000 MB eventsdNch/d ~ 50 !
SPS RHIC LHC
# of partons in proton
3 + g(x > 2GeV)
4 10 30Phobos Cu-Cu
QM08 J. Schukraft3
Isn’t that jet physics ??Isn’t that jet physics ?? pp high multiplicity = Jets, we’ve been there (eg LEP)
can one separate the ‘soft’ from the ‘hard’(e.g with veto on jets) ?
CDF (Phys.Rev.D65:072005,2002 ) STAR (Phys.Rev.D74:032006,2006)
Inclusive Soft
Hard
There are ‘soft’ eventsup to very high Nch !
QM08 J. Schukraft4
The first result is already knownis already known NNpartpart scaling won’t work scaling won’t work with high multiplicity pp !!
I’m sure WB and BW will work out some other scaling relation..
Cu+CuPreliminary
15-25%, Npart = 61
PHOBOS PHOBOS
62.4 GeV 200 GeV
Au+Au45-50%,Npart = 62
Cu+CuPreliminary
15-25%, Npart = 60
Au+Au45-55%, Npart = 56
QM08 J. Schukraft5
STAR
More interesting studiesMore interesting studies Particle production: How do we approach fully thermal ratios ??
strangeness under-saturation in pp: canonical suppression, disconnected sub-volumes, missing final state interactions,… a ‘thermal analysis’ in pp from dNch/dy < 5 to > 50 would seem quite interesting
comparison between pp and AA at similar dN/dy volume/density/lifetime effects ??
some results exist from FNAL and RHIC limited statistics (much) lower dN/dy no separation soft/hard
E735 Fermilab Nch
<p
T>
Protons
Kaons
Pions
QM08 J. Schukraft6
From merely exotic From merely exotic to totallyto totally crazycrazy
Hadronic FSI ? dn/dy ~ 100 => rescattering => radial flow ? does size and shape matter for a proton ? => HBT, elliptic flow ?
Are partons feeling the pressure ?? coalescence, flow scaling with quark number ?? lepton & photons from parton annihilation ??
Jet quenching, Quarkonia suppression ??? you name it, LHC has it * …..
* maybe. No money back guarantee