From: yin.zhongbao@fi.uib.no
Date: Thu Sep 25 2003 - 14:51:40 EDT
Dear Michael,
First thank you for your comments.
To understand the species dependence of high pt suppression, one has
to think out where and how those high pt particles produced. If one
assumes that high pt particles are produced by hard parton fragmentation
then it is quite difficult to understand why there is so much different
suppression from meson to baryon. That's why it is so interesting for
theory to understand the hadronization mechanism (certainly it is not
clear at all till now even though there are some phenomenological theory e.g.
string theory). Now heavy ion collisions provide people a few environment
to try to understand how particles are hadronized. Certainly if we trust
hydro-dynamic description of the space-time evolution of relativistic
heavy ion collision, hadronization is also an important issue need
to be understand. It is relate to how to understand the phase transition
from QGP to hadron gas. That might be the reason why it is so interesting
for theorist to understand the different suppression between meson and
baryon. There are quite a lot papers released to address such issue, for
detail refer to references in [2]. Well, for us, we only show what our
data look like...
Best regards,
Zhongbao
> WHAT WE WANT HERE IS NOT TO UNDERSTAND HADRONIZATION ITSELF BUT RATHER
> HOW ENERGY LOSS MIGHT DEPEND ON THE NATURE OF THE HIGH PT PARTICLE.
> FOR EXAMPLE WHAT DOES THEORY SAY ABOUT THE ENERGY LOSS FOR PARTICLES THAT
> BECOME MESONS VERSUS THOSE THAT BECOME HADRONS.
> There have been recent attempts to describe the different behaviour of
> baryons and mesons through different hadronization mechanisms [2] (e.g.
> gluon junction, recombination or parton coalescence).
>
> The BRAHMS spectrometers have the unique ability to identify hadrons
> over a broad range of rapidity and transverse momenta. This allows us
> to study the high $p_{\rm T}$ hadron production mechanism through
> rapidity dependence of hadron spectra and particle composition.
>
> In this talk the BRAHMS collaboration presents new measurements for
> identified
> high $p_{\rm T}$ charged hadron production in Au+Au and d+Au collisions at
> different rapidities and centralities. (Anti)-Proton spectra at midrapidity
> were measured up to $p_{\rm T} = 3.5$ GeV/c, $\pi^-$ spectra at forward
> rapidity cover $p_{\rm T}$ range up to 4.0 GeV/c. First results show %MJM
> a clear suppression of $\pi^-$ at forward rapidity ($y = 2.2$).
> Particle composition will further be discussed
> in terms of $p/h^+$ and $\bar{p}/h^-$ at
> midrapidity and of $\pi^-/h^-$ at forward rapidity. \\
>
>
> \par
> [1] K. Adcox et al., Phys. Rev. Lett. 88 (2002) 242301;\ \
> C. Adler et al., Phys. Rev. Lett. 86 (2001) 4778;\ \
> S. S. Adler et.al., nucl-ex/0307022 .\\
> AND BRAHMS
>
> [2] Z. W. Lin and C. M. Ko, Phys. Rev. Lett. 89 (2002) 202302; \ \
> S. A. Voloshin, Nucl. Phys. A715 (2003) 379c; \ \
> D. Molnar and S. A. Voloshin, nucl-th/0302014; \ \
> Z. W. Lin and D. Molnar, nucl-th/0304045.\\
>
> \end{document}
>
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>
> -----Original Message-----
> From: Jens Ivar Jordre [mailto:jensivar.jordre@fi.uib.no]
> Sent: Thu 9/25/2003 10:24 AM
> To: BRAHMS List
> Cc:
> Subject: Updated QM abstracts from Bergen.
>
> Dear collaborators.
>
> Here are updated abstracts from Bergen. Please read and comment.
>
> Best wishes from
> Zhongbao and Jens Ivar
>
>
--
-----------------------------------------------------
Zhongbao YIN Phone: +47-55-582792 (O)
Address: +47-55-276803 (H)
Fantoftveien 14G 466 E-mail:
5075 Bergen Yin.Zhongbao@fi.uib.no
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