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