List of complementary measurements suggested for discussion: 1)Flow implies Mt scale breaking: -------------------------------- Flow adds extra Pt. mt spectrum should have universal slope: exp(-alpha * sqrt(pt^2+mt^2)) 2)Particle composition: ---------------------- Baron/meson ratio strangeness 3) kt domain: ----------- Don't restrict to same kt range for both particles 4)Remove the leading jet ------------- Eliminate or enhance (mini)jet content by trigger use 3-particle correlation 5)Event shape of the UE (after removing jet): -------------------------------------------- Disk-like UE, a la Pierre Van Mechelen 6) Quantities to 'measure' correlations ------------------------------------- Kumulants in forward-backward rapidity ranges 7)Can one extend eta range? -------------------------- CMS HF calorimeter 8) Energy dependence: --------------------- Look in Tevatron data.. Lower energy experiments RHIC pp, or extrapolations to very peripheral Can we have more 900 GeV data st LHC? general comments: ----------------- Rick Field: MC does not only disagree with data in ridge, but everywhere Correlations is complex variable, how do events actually look like: event shapes (sphericity) Plot jet of leading jet versus multiplicity: is increase of multiplicity purely due to increase of leading jet pt? UE: is it a back to back topology? or are there jets in transverse region Higher order correlations in QCD that aren't implemented in MC: ISR and FSR tends to populate one plane S Chekanov: peak at zero is huge compared to 'signal': few percent event, can you completely exclude beam gas Other measurement by ZEUS: ratio of deuteron/antideuteron=3 observed, similar to HI. Naive expectation from fragmentation is 1. never really understood. R. Snellings: Alice has smaller eta coverage with tracker but has forward multiplicity counters AND high multiplicity trigger Particle composition in HI: baryon & strangeness differences between jet region and the ridge Fritz Bopp: PHOJET is often used in comparison but not in this case. PHOJET produces lots of small jets at high multiplicity Comment: PHOJET cannot produce multiplicities above 100 as far as we've seen. Comment: other signatures from hot dense matter to be checked, such as mt distributions Eddi: f-B correlations Pierre Van Mechelen: MPI's aligned in one plan along impact parameter vector--> resulting particles have similar phi Initial states have different x--> Uniform distribution in eta Q: How about centrality dependence of ridge? Q: Why is the effect only there for intermediate Pt, does this fit ion the explanations from 'pure' QCD a la Ochs or Gustafsson Q to G. Gustaffson: can one introduce phi-correlations in PYTHIA MPI model? Same question asked in past by HI community. is being investigated in dipole cascade model Elliptic flow disappears for central HI collisions Tokarev: Rapidity plateau in pp is so wide, compared to Cu+Cu, is there a connection? narrow rapidity distribution will probably not show ridge... W. Ochs: Standard QCD effect is plausible. Is it really related to high multiplicities, or just to jet topology and gluon radiation in between? If standard QCD, should be seen in standard jet trigger : draws cross like gluon topology with 2 dipoles. Big peak at deltaeta=0, deltaphi=0 comes from single jet Why does MC doesn't show ridges that he expects in any case. Bigger the jet energy, the stronger the effect should become in case of QCD effect. ---> Look at the height of your ridge as function of jet energy --> multiplicity as such is not triggering the effect, it is the jet itself that triggers it If you move the peak, according to the real rapidity of the leading jet, you will get asymmetries corresponding to the angle under which the color dipoles have emitted most radiation. measure 1/(1-costheta_12)/(1-costheta23) In any case the effect (and asymmetries) should increase with jet energy. If so, it is simple QCD. parton cascades are cut off in Pythia at relatively high q0--> no phase space for gluon Gustafsson: those emissions are in there as FSR, and they should be put in a plane just like ARIADNE, but you currently loose it in the angular ordering Comment: Other high multiplicity anomalies at lower energies? Tom Trainor: Star paper in PRD on multiplicity dependence of min bias jets in pp, probability of jet per event increases by factor 100 when multiplicity increases. Properties don't change: jet spectrum is so steep that it is more economical to produce more low pt jets. Broadening of jet peak in HI events: Not necessary that ridge belongs to jet peak. Stay in 2D, don't just make projections in f-b correlations Start from min bias sample and not just particular bin in pt of tracks and multiplicity. y_t-y-t plane(make diagonal slices, and bins, but look at whole picture as well) and deltaeta-deltaphi plane. Shows pure 2d Gaussian shape for 200 GeV Au-Au mid-central collisions (slide 17 of his ISMD talk, top middle plot) Cos(2phi) piece is identified with elliptic flow. Take this piece out. Slide 18 of his talk: centrality dependence: energy dependency fixed factor of deltarho(2)/SQRT(Rhoref) and centrality dependence. Extrapolations in centrality to p-p collisions hits a non zero value (top right plot) T.Csorgo: BFS collaboration 52.6 GeV collisions, similar effect found: increase of correlations in small region in rapidity and phi, complemented by enhancement at larger delta-eta. Important to study sqrt(s) dependence. is it really hydro behavior or string/hot spot?? Y. Hamma: # particle correlations: show a way to get rid of the jet peak and isolate the ridge. take leading jet pt(called 1) and your 2 particles(2 and 3) and take delta12(smallest isolated particle, delta eta < 0.2, small deltaphi) --> jet peak and away side ridge. and delta13 (delta eta > 1.5). Look at correlation with 'trigger' and second particle 3, you see away side ridge from Hama's hydro model. What does CMS observe: CMS observes near side ridge, nut must also have an away side ridge, buried under the big backward 'hill' due to backscattering at deltaphi=pi. Eliminate the backward jet and see what remains.