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Michael Murray1 Global Detectors Flavor Dynamics Michael Murray for BRAHMS C. Arsene 12, I. G. Bearden 7, D. Beavis 1, S. Bekele 12, C. Besliu 10, B. Budick.

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Presentation on theme: "Michael Murray1 Global Detectors Flavor Dynamics Michael Murray for BRAHMS C. Arsene 12, I. G. Bearden 7, D. Beavis 1, S. Bekele 12, C. Besliu 10, B. Budick."— Presentation transcript:

1 Michael Murray1 Global Detectors Flavor Dynamics Michael Murray for BRAHMS C. Arsene 12, I. G. Bearden 7, D. Beavis 1, S. Bekele 12, C. Besliu 10, B. Budick 6, H. B ø ggild 7, C. Chasman 1, C. H. Christensen 7, P. Christiansen 7, H.Dahlsgaard 7, R. Debbe 1, J. J. Gaardh ø je 7, K. Hagel 8, H. Ito 1, A. Jipa 10, E.B.Johnson 11, J. I. J ø rdre 9, C. E. J ø rgensen 7, R. Karabowicz 5, N. Katrynska 5,E. J. Kim 11, T. M. Larsen 7, J. H. Lee 1, Y. K. Lee 4,S. Lindahl 12, G. L ø vh ø iden 12, Z. Majka 5, M. J. Murray 11,J. Natowitz 8, C.Nygaard 7 B. S. Nielsen 7, D. Ouerdane 7, D.Pal 12, F. Rami 3, C. Ristea 8, O. Ristea 11, D. R ö hrich 9, B. H. Samset 12, S. J. Sanders 11, R. A. Scheetz 1, P. Staszel 5, T. S. Tveter 12, F. Videb æ k 1, R. Wada 8, H. Yang 9, Z. Yin 9, I. S. Zgura 2 BNL, Bucharest, Strasbourg, John Hopkins, Krakow, NYU, NBI, Kansas, Oslo

2 Michael Murray2 What are the dynamics of strange & light quarks? Baryon number is clearly transported in both rapidity and p T. Antibaryons and strange quarks are created How do these different flavors interact Can we learn something about the initial state of the system from their interaction. From apparatus => data => comparison to NLO QDC => inference concerning flow and limiting fragmentation => thermal descriptions versus rapidity => half finished wild speculation

3 Michael Murray3 Global Detectors Broad Range HAdronic Magnetic Spectrometers

4 Michael Murray4 TIME-OF-FLIGHT 0<  <1 (MRS) 1.5<  <4 (FS) p max (2  cut) TOFW (GeV/c) TOFW2 (GeV/c) TOF1 (GeV/c) TOF2 (GeV/c) K/  K/p Ring radius vs momentum gives PID  / K separation 25 GeV/c Proton ID up to 35 GeV/c (2 settings) RICH Particle Identification

5 Michael Murray5 Invariant yields over a broad range of phase space

6 Michael Murray6 N  = 120  35 Finding  through weak decay to K +,K - Invariant mass of K + K - pair (GeV/c 2 ) Preliminary AuAu y~1 minimum bias, 200GeV

7 Michael Murray7 dN/dy = 2.09  1.00  0.25 T = 354  109  35 MeV Consistent with STAR at y=0 Fitting m T spectra gives dN/dy and T

8 Michael Murray8 pp => , k, p at 200GeV p T (GeV/c) PRL 98,  =2p T  =1/2p T

9 Michael Murray9 Baryon transport for pp at  s = 62GeV dN/dy =0.7 e y-yb => dN/dx=c Rapidity dN dy Models such as Pythia seriously underestimate the yield of high p T protons at forward rapidities Preliminary

10 Michael Murray10 Baryon Transport in AuAu “net”proton AGS SPS RHIC 62 RHIC 200 LHC 5500 dN/dy (BRAHMS preliminary) For AuAu collisions a parton my be hit multiple times and the rapidity distribution flattens out

11 Michael Murray11  y = A -B e -ybeam AuAu rapidity loss flattens out between SPS & RHIC ybeam Peak of proton dN/dy should fall in acceptance of CASTOR at LHC

12 Michael Murray12 Limiting fragmentation pp =>  , k  y-ybeam

13 Michael Murray13 Limiting fragmenation even works for p, pbar y-ybeam

14 Michael Murray14 Limiting Fragmentation also works in AuAu BRAHMS Preliminary + NA49 dN dy 1 N part y - ybeam

15 Michael Murray15 PRC Preliminary AuAu at √s NN = 200GeV, 0-50% central Elliptic flow, v 2 (p T ) is independent of rapidity decreases with y because decreases with y

16 Michael Murray16 V 2 (p T ) scaling at central & forward rapidity

17 Michael Murray17 Yields of produced particles are Gaussian Central 62GeV AuAu =>  , K  pbar Preliminary rapidity dN/dy

18 Michael Murray18 At each rapidity assume chemical equilibrium and strangeness neutrality and Are different regions of rapidity in chemical equilibrium?

19 Michael Murray19 Chemical freeze-out BRAHMS PRELIMINARY K - /K + ratios seem to be controlled by pbar/p

20 Michael Murray20 Does pbar/p control rapidity dependence strangeness in pp too? Not so good here Note for pp we have to be careful to conserve quantum numbers in each event

21 Michael Murray21 Fit  ±, K ±, p and pbar dN/dy to a temperature and chemical potentials for strange & light quarks T=116  9 MeV T=148  3 MeV T=160 MeV "THERMUS -- A Thermal Model Package for ROOT", S. Wheaton and J. Cleymans, hep-ph/ Assumption of strangeness neutrality could be checked by comparing to  yields

22 Michael Murray22 Are protons black, white holes? Colour charges are confined If we change the gravitational force with the strong nuclear force then R ~ 1fm.

23 Michael Murray23 Black Holes and the uncertainty principle + -

24 Michael Murray24 Black Holes radiate with T = 1/(8  GM) +

25 Michael Murray25 If black holes are charged the temperature changes Temperature Charge

26 Michael Murray26 Slide 3 Search for charge white RHIC M => E Q => B G => 1/2 

27 Michael Murray27 First look for white holes in AuAu collisions STAR 200GeV AuAu

28 Michael Murray28 First look for white holes in AuAu collisions These points have comparable p-pbar Assuming white hole hypothesis works at 200GeV implies T=137  5 MeV for 63GeV, y=0

29 Michael Murray29 Next Steps Do thermal analysis as a function of centrality Use particle abundances and average momenta to estimate dE T /dy vs √S and centrality. Test if “White Hole” hypothesis can explain BRAHMS data in terms of thermal distributions

30 Michael Murray30 Conclusions NLO pQCD has trouble describing p and pbar spectra for the forward region of pp collisions A wide range of phenomena obey limiting fragmentation Elliptic flow at a given p T is independent of y Particle yields at a given rapidity can be described within a thermal framework. The temperature falls with √S and y Somehow we need to explain very rapid, perhaps instant, thermalization of the system with parameters driven by the baryon density. We are investigating the charged “white hole” hypothesis.

31 Michael Murray31 Backups

32 Michael Murray32 Particle ratios vs rapidity

33 Michael Murray33 Acceleration and radiation A stationary observer in the blue region sees the thermal radiation of temperature T = a/2  Pictures from Castorina, Kharzeev & Satz hep-ph/ Mass m 1/a

34 Michael Murray34 For NA27, the K - /K + ratio seems to be high NA49 could clarify this


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