3,147 research outputs found
Proton-proton multiplicity distributions at LHC and the Pomeron intercept
We compute the proton-proton multiplicity distributions at LHC energies in
the framework of a multiple scattering model assuming a Poisson distribution
for each inelastic collision. Multiple scattering is essential to broaden the
multiplicity distribution. We obtain approximate KNO scaling for small
pseudo-rapidity intervals () and sizable KNO scaling violations
for larger ones, in agreement with experiment.Comment: 6 pages, 2 figure
Multiplicities and suppression at LHC energies
We present our predictions on multiplicities and suppression at LHC
energies. Our results take into account shadowing effects in the initial state
and final state interactions with the hot medium. We obtain 1800 charged
particles at LHC and the suppression increases by a factor 5 to 6
compared to RHIC.Comment: 2 pages, 2 figures. Contributed to Workshop on Heavy Ion Collisions
at the LHC: Last Call for Predictions, Geneva, Switzerland, 14 May - 8 Jun
200
Elliptic Flow in a Final State Interaction Model
We propose a final state interaction model to describe the fixed
suppression of the yield of particles at all values of . We make an
extension of the model to the motion in the transverse plane which introduces a
dependence of the suppression on the azimuthal angle . We obtain
values of the elliptic flow close to the experimental ones for all
values of .Comment: 4 pages, 6 figures, proceedings of XLIst Rencontres de Moriond: QCD
and Hadronic Interactions at high energ
Radial Flow in a Final State Interaction Model
In the framework of a final state interaction model, we show that the
so-called radial flow, i.e. the almost linear increase of the inverse slope
with the mass of the produced particle, is already contained in the initial
condition -- with a slope (the so-called strength of the average
radial transverse flow) which is larger than the measured one. While the
precise value of the slope depends on the details of the model, the above
result has a very general basis -- namely the increase with increasing of
the fixed suppression, in the low region.Comment: 9 pages, 2 figure
Large transverse momentum suppression at RHIC: Shadowing and absorption
We propose a model of suppression of 's based on two different
effects: at low we take into account the shadowing corrections, which are
non-linear and essential for the description of the inclusive spectra, while at
large the suppression is produced through the interaction of the large
pion with the dense medium created in the collision. The main features of
the data on and collisions at RHIC energies are reproduced both at
mid and at forward rapidities.Comment: 6 pages, 2 figures. Contribution to the 8th Workshop on
Non-Perturbative Quantum Chromodynamics, June 7-11, 2004, l'Institut
Astrophysique de Paris, Franc
Frustration in Biomolecules
Biomolecules are the prime information processing elements of living matter.
Most of these inanimate systems are polymers that compute their structures and
dynamics using as input seemingly random character strings of their sequence,
following which they coalesce and perform integrated cellular functions. In
large computational systems with a finite interaction-codes, the appearance of
conflicting goals is inevitable. Simple conflicting forces can lead to quite
complex structures and behaviors, leading to the concept of "frustration" in
condensed matter. We present here some basic ideas about frustration in
biomolecules and how the frustration concept leads to a better appreciation of
many aspects of the architecture of biomolecules, and how structure connects to
function. These ideas are simultaneously both seductively simple and perilously
subtle to grasp completely. The energy landscape theory of protein folding
provides a framework for quantifying frustration in large systems and has been
implemented at many levels of description. We first review the notion of
frustration from the areas of abstract logic and its uses in simple condensed
matter systems. We discuss then how the frustration concept applies
specifically to heteropolymers, testing folding landscape theory in computer
simulations of protein models and in experimentally accessible systems.
Studying the aspects of frustration averaged over many proteins provides ways
to infer energy functions useful for reliable structure prediction. We discuss
how frustration affects folding, how a large part of the biological functions
of proteins are related to subtle local frustration effects and how frustration
influences the appearance of metastable states, the nature of binding
processes, catalysis and allosteric transitions. We hope to illustrate how
Frustration is a fundamental concept in relating function to structural
biology.Comment: 97 pages, 30 figure
J/psi suppression at SPS and RHIC in the comovers approach
The NA50 collaboration data on the suppression are compared with the
results obtained in a comovers approach based on the Dual Parton Model (DPM).
Predictions for the suppression versus the charged multiplicity -
measured in the rapidity region of the dimuon trigger - are given for SPS and
RHIC energies.Comment: 4 pages, contribution to QM200
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