4,409 research outputs found
High-density QCD with CMS at the LHC
The capabilities of the CMS experiment to explore the rich heavy-ion physics
programme offered by the CERN Large Hadron Collider (LHC) are summarised.
Various representative measurements in Pb-Pb collisions at sqrt(s) = 5.5 TeV
are covered. These include "bulk" observables (charged hadron multiplicity,
low-pT inclusive hadron spectra and elliptic flow) which provide information on
the collective properties of the system; as well as perturbative processes
(high-pT hadrons, jets, gamma-jet and quarkonium production) which yield
"tomographic" information of the densest phases of the reaction.Comment: 8 pages, 7 figs. Proceeds plenary talk Quark-Matter'08, Jaipur,
India. To appear in J. Phys.
High-energy heavy-ions physics: from RHIC to LHC
A selection of experimental results in high-energy nucleus-nucleus collisions
after five years of operation of the Relativistic Heavy-Ion Collider (RHIC) is
presented. Emphasis is put on measurements that provide direct information on
fundamental properties of high-density QCD matter. The new experimental
opportunities accessible at LHC are introduced, in particular those that may
help clarify some of the current open issues at RHIC.Comment: A few misprints corrected. Matches version to appear in NP
Impact of LHC Run-1 on particle astrophysics
An overview of the impact of the first three years of LHC operation on two of
the most important open questions in astroparticle physics is presented.
Measurements in proton-proton collisions at the energy frontier that provide
valuable information on the identity of the highest-energy particles in the
cosmos as well as new constraints on the nature of dark matter, are summarized.Comment: 7 pages, 8 figures. Proceedings invited plenary talk at "2nd Intl.
Conf. on New Frontiers in Physics" (ICNFP 2013) in Kolymbari, Crete. To
appear in Eur.Phys.J.Con
review (2016)
The current world-average of the strong coupling at the Z pole mass,
, is obtained from a comparison of
perturbative QCD calculations computed, at least, at
next-to-next-to-leading-order accuracy, to a set of 6 groups of experimental
observables: (i) lattice QCD "data", (ii) hadronic decays, (iii) proton
structure functions, (iv) event shapes and jet rates in collisions,
(v) Z boson hadronic decays, and (vi) top-quark cross sections in p-p
collisions. In addition, at least 8 other extractions, usually with
a lower level of theoretical and/or experimental precision today, have been
proposed: pion, , W hadronic decays; soft and hard fragmentation
functions; jets cross sections in pp, e-p and -p collisions; and photon
F structure function in collisions. These 14
determinations are reviewed, and the perspectives of reduction of their present
uncertainties are discussed.Comment: 4 pages, 2 figures. Minor changes. Version submitted to Proceedings
Moriond QCD 201
Physics case of FCC-ee
The physics case for electron-positron beams at the Future Circular Collider
(FCC-ee) is succinctly summarized. The FCC-ee core program involves
collisions at = 90, 160, 240, and 350 GeV with multi-ab
integrated luminosities, yielding about 10 Z bosons, 10 WW
pairs, 10 Higgs bosons and 410 pairs per year.
The huge luminosities combined with keV knowledge of the c.m.
energy will allow for Standard Model studies at unrivaled precision. Indirect
constraints on new physics can thereby be placed up to scales 7 and 100 TeV for particles coupling respectively to the Higgs
and electroweak bosons.Comment: 8 pages, 6 figures. Proceedings LFC15: Physics Prospects for Linear
and Other Future Colliders, ECT*, Trento, Oct. 201
Physics at the FCC-ee
The physics program accessible in collisions at the Future Circular
Collider (FCC-ee) is summarized. The FCC-ee aims at collecting multi-ab
integrated luminosities in at = 90, 160, 240, and 350 GeV,
yielding 10 Z bosons, 10 WW pairs, 10 Higgs bosons
and top-quark pairs per year. Such huge data samples combined
with a c.m. energy uncertainty will allow for Standard
Model measurements with unparalleled precision and searches for new physics in
regions not probed so far. The FCC-ee will be able to (i) indirectly discover
new particles coupling to the Higgs and electroweak bosons up to scales
7 and 100 TeV; (ii) perform competitive SUSY tests at the
loop level in regions beyond the LHC reach; and (iii) achieve the best
potential in direct collider searches for dark matter and sterile neutrinos
with masses below 60 GeV.Comment: 8 pages, 8 figures. Proceedings 17th Lomonosov conference on
Elementary Particle Physics, Moscow, Aug. 2015. World Scientific, to appear.
arXiv admin note: text overlap with arXiv:1601.06640
Higgs and Beyond the Standard Model physics with the FP420 detector at the LHC
The physics case of the FP420 R&D project aiming at the installation of
proton detectors in the LHC tunnel at 420 m from the ATLAS and CMS interaction
points, is presented. The motivations of the measurements accessible with FP420
-- exclusive Higgs production (pp --> p H p) and photon-induced processes (pp
--> p gamma p --> p X p, pp --> p gamma gamma p --> p X p, where X is sensitive
to new physics) -- are outlined.Comment: Proceedings Moriond-QCD 2009. 5 pages, 3 fig
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