25 research outputs found
Describing dynamical fluctuations and genuine correlations by Weibull regularity
The Weibull parametrization of the multiplicity distribution is used to
describe the multidimensional local fluctuations and genuine multiparticle
correlations measured by OPAL in the large statistics sample. The data are found to be well reproduced by the Weibull model
up to higher orders. The Weibull predictions are compared to the predictions by
the two other models, namely by the negative binomial and modified negative
binomial distributions which mostly failed to fit the data. The Weibull
regularity, which is found to reproduce the multiplicity distributions along
with the genuine correlations, looks to be the optimal model to describe the
multiparticle production process.Comment: 10 pages, 2 figure
Effective-energy universality approach describing total multiplicity centrality dependence in heavy-ion collisions
The recently proposed participant dissipating effective-energy approach is
applied to describe the dependence on centrality of the multiplicity of charged
particles measured in heavy-ion collisions at the collision energies up to the
highest LHC energy of 5 TeV. The effective-energy approach relates multihadron
production in different types of collisions, by combining, under the proper
collision energy scaling, the constituent quark picture with Landau
relativistic hydrodynamics. The measurements are shown to be well described in
terms of the centrality-dependent effective energy of participants and an
explanation of the differences in the measurements at RHIC and LHC are given by
means of the recently introduced hypothesis of the energy-balanced limiting
fragmentation scaling. A similarity between the centrality data and the data
from most central collisions is proposed pointing to the central character of
participant interactions independent of centrality. The findings complement our
recent investigations of the similar midrapidity pseudorapidity density
measurements extending the description to the full pseudorapidity range in view
of the considered similarity of multihadron production in nucleon interactions
and heavy-ion collisions.Comment: Same as published versio
Event patterns from negative pion spectra in proton-proton and nucleus-nucleus collisions at SPS
Rapidity-dependent transverse momentum spectra of negatively charged pions
measured at different rapidities in proton-proton collisions at the Super
Proton Synchrotron (SPS) at various energies within its Beam Energy Scan (BES)
program are investigated by using one- and two-component standard distributions
where the chemical potential and spin property of particles are implemented.
The rapidity spectra are described by a double-Gaussian distribution. At the
stage of kinetic freeze-out, the event patterns are structured by the scatter
plots in the three-dimensional subspaces of velocity, momentum and rapidity.
The results of the studies of the rapidity-independent transverse mass spectra
measured at mid-rapidity in proton-proton collisions are compared with those
based on the similar transverse mass spectra measured in the most central
beryllium-beryllium, argon-scandium and lead-lead collisions from the SPS at
its BES energies.Comment: 17 pages, 9 figure
Cosmological analogies in the search for new physics in high-energy collisions
In this paper, analogies between multiparticle production in high-energy
collisions and the time evolution of the early universe are discussed. A common
explanation is put forward under the assumption of an unconventional early
state: a rapidly expanding universe before recombination (last scattering
surface), followed by the CMB, later evolving up to present days, versus the
formation of hidden/dark states in hadronic collisions followed by a
conventional QCD parton shower yielding final-state particles. In particular,
long-range angular correlations are considered pointing out deep connections
between the two physical cases potentially useful for the discovery of new
physics.Comment: 9 pages, 5 figure
Photon mass limits from fast radio bursts
International audienceThe frequency-dependent time delays in fast radio bursts (FRBs) can be used to constrain the photon mass, if the FRB redshifts are known, but the similarity between the frequency dependences of dispersion due to plasma effects and a photon mass complicates the derivation of a limit on mÎł. The dispersion measure (DM) of FRB 150418 is known to âŒ0.1%, and there is a claim to have measured its redshift with an accuracy of âŒ2%, but the strength of the constraint on mÎł is limited by uncertainties in the modelling of the host galaxy and the Milky Way, as well as possible inhomogeneities in the intergalactic medium (IGM). Allowing for these uncertainties, the recent data on FRB 150418 indicate that mÎłâČ1.8Ă10â14 eVcâ2 (3.2Ă10â50 kg), if FRB 150418 indeed has a redshift z=0.492 as initially reported. In the future, the different redshift dependences of the plasma and photon mass contributions to DM can be used to improve the sensitivity to mÎł if more FRB redshifts are measured. For a fixed fractional uncertainty in the extra-galactic contribution to the DM of an FRB, one with a lower redshift would provide greater sensitivity to mÎł
Searching for hidden sector in multiparticle production at LHC
We study the impact of a hidden sector beyond the Standard Model, e.g. a Hidden Valley model, on factorial moments and cumulants of multiplicity distributions in multiparticle production with a special emphasis on the prospects for LHC results
Introduction to a New Open Access Journal by MDPI: Physics
Herewith, we launch a new MDPI journal, Physics, for which I am honored to serve as Editor-in-Chief. [...
Searching for new physics with three-particle correlations in collisions at the LHC
New phenomena involving pseudorapidity and azimuthal correlations among final state particles in collisions at the LHC can hint at the existence of hidden sectors beyond the Standard Model. In this paper we rely on a correlated-cluster picture of multiparticle production, which was shown to account for the ridge effect, to assess the effect of a hidden sector on three-particle correlations concluding that there is a potential signature of new physics that can be directly tested by experiments using well-known techniques.New phenomena involving pseudorapidity and azimuthal correlations among final-state particles in pp collisions at the LHC can hint at the existence of hidden sectors beyond the Standard Model. In this paper we rely on a correlated-cluster picture of multiparticle production, which was shown to account for the ridge effect, to assess the effect of a hidden sector on three-particle correlations concluding that there is a potential signature of new physics that can be directly tested by experiments using well-known techniques