slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Ramiro Debbe for the BRAHMS collaboration Physics Department PowerPoint Presentation
Download Presentation
Ramiro Debbe for the BRAHMS collaboration Physics Department

Loading in 2 Seconds...

play fullscreen
1 / 14

Ramiro Debbe for the BRAHMS collaboration Physics Department - PowerPoint PPT Presentation


  • 152 Views
  • Uploaded on

Forward Identified Particle Production in d+Au and p+p collisions at √s NN =200 GeV. 2004 Fall Meeting Division of Nuclear Physics. Ramiro Debbe for the BRAHMS collaboration Physics Department. Outline of the presentation.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Ramiro Debbe for the BRAHMS collaboration Physics Department' - pakuna


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Forward Identified Particle Production in d+Au and p+p collisions at √sNN=200 GeV

2004 Fall Meeting Division of Nuclear Physics

Ramiro Debbe

for theBRAHMScollaboration

Physics Department

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide2

Outline of the presentation

  • Will show RdAu for negative identified particles using our RICH to construct anti-proton and negative pion to negative charged particle ratios.
  • Present a study of the composition of the positive particle pt distribution at 4 degrees using proton/pion and kaon/pion ratios.
  • Compare particle ratios extracted from p+p data collected at 4 degrees with PYTHIA simulation.
  • Summarize

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide3

Use of theBRAHMSRICHto identify particles

We make use of already produced spectra and RdAu factors and use the RICH at high momentum to bypass the long process of invariant yield extraction.

17 GeV/c

Above the selected momentum threshold the RICH is ~94% efficient.

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide4

Using ratios to obtain the RdAu of identified negative particles.

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide5

Ratios: pion over charged (negatives)

d + Au

p +p

The conversion from RdA(h-) to RdAu(-) is done point by point.

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide6

Anti-proton/negative charged particles in d+Au at 4 degrees

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide7

Ratio of anti-proton to negative particles in p+p at 4 degrees

The conversion from RdAu(h-) to RdAu(p) makes use of fits to the ratios of anti-proton to negative charged hadrons. Error propagation includes all parameter correlations.

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide8

RdAu for anti-protons and pions at ~3 (min bias)

This will not be the first time baryons show a different nuclear modification factor.

PHENIX reported such difference at y=0 in AuAu and dAu systems

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide9

The difference between positive and negative hadrons in dAu at 4 degrees

This measured difference (≥2 at 3GeV/c) is not easily explained if pion production is dominant. (NLO pQCD)

It has been early dubbed as “beam fragmentation”

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide10

d+Au positives

As seen in the figure on the right there are roughly as many protons as pions at high pt at forward rapidities (y~3) in d+Au

Same information as above but this time we show how h+ is composed of protons, pions, and kaons.

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide11

The composition of h+ yields in dAu at ~3

Isospin considerations set: + = -

We make use of the measured ratio -/h-~0.8

Independent of momentum to write:

h+ = 0.8h-( 1 + p/+ + K/+)

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide12

Comparison of particle ratios extracted from p+p data at 4 degrees and PYTHIA 6.303

For protons we find a remarkable difference that may indicate other processes besides parton fragmentation.

We measure a small excess of kaons and see an emerging trend that suffers from low statistics at high pt.

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide13

Summary and outlook

  • With the use of particle ratios obtained with our RICH we have shown that baryons and mesons have a different behavior as can be seen in the nuclear modification factors of anti-protons and pions at ~3 in d+Au collisions.
  • We have shown the composition of positive particles at high pt and rapidity 3 in d+Au collisions.
  • We compared particle ratios extracted from p+p data collected at 4 degrees and find strong disagreement with PYTHIA calculations.
  • BRAHMS measurements continue to show that Forward Physics in hadron colliders is fertile ground for discovery.

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL

slide14

The BRAHMS Collaboration

I. Arsene, I.G. Bearden, D. Beavis, C. Besliu, B. Budick, H. Bøggild, C. Chasman,

C. H. Christensen, P. Christiansen, J. Cibor, R. Debbe, E. Enger J. J. Gaardhøje,

M. Germinario, K. Hagel, O. Hansen, A. Holme, A.K. Holme, H. Ito, A. Jipa,

J.I. Jørdre, F. Jundt, C.E.Jørgensen, R. Karabowicz, E.J. Kim, T. Kozik,

T.M. Larsen, J.H. Lee, Y. K.Lee, S. Linda, G. Løvhøjden, R. Lystad, Z. Majka,

A. Makeev, M. Mikelsen, M. Murray, J. Natowitz, B. Neumann, B.S. Nielsen,

K. Olchanski, D. Ouerdane, R.Planeta, F. Rami, C. Ristea, O. Ristea, D.Roehrich,

B. H. Samset, D. Sandberg, S. J. Sanders, R.A.Sheetz, P. Staszel, T.S. Tveter,

F.Videbæk, R. Wada,Z. Yin and I. S. Zgura

Brookhaven, Strasbourg, Krakov, Johns Hopkins, NYU, Niels Bohr.

Texas A&M, Bergen, Bucharest, Kansas, Oslo

DNP2004 Oct. 27-30 Hyatt Regency Chicago IL