We investigate the potentialities offered by the study of J/ψ exclusive photo-production in ultra-peripheral collisions at a fixed-target experiment using the proton and lead LHC beams (generically ...denoted as AFTER@LHC) on hydrogen targets and at RHIC in the collider mode. We compare the expected cross sections in both set-ups. Studying Single-Transverse-Spin Asymmetries (AN) in such a process provides a direct path to the proton Generalised Parton Distribution (GPD) Eg(x,ξ,t). We evaluate the expected precision on AN for realistic conditions with the LHCb detector in pH↑ and PbH↑ collisions. We also discuss prospects with polarised deuterium and helium targets in the case of AFTER@LHC.
A
bstract
In this paper we revisit the idea of measuring the magnetic dipole moments of the charm baryons and, in particular, of
Λ
c
+
by studying the spin precession induced by the strong effective ...magnetic field inside the channels of a bent crystal. We present a detailed sensitivity study showing the feasibility of such an experiment at the LHC in the coming years.
We review the context, the motivations and the expected performances of a comprehensive and ambitious fixed-target programme using the multi-TeV proton and ion LHC beams. We also provide a detailed ...account of the different possible technical implementations ranging from an internal wire target to a full dedicated beam line extracted with a bent crystal. The possibilities offered by the use of the ALICE and LHCb detectors in the fixed-target mode are also reviewed.
Being used in the fixed-target mode, the multi-TeV LHC proton and lead beams allow for studies of heavy-flavour hadroproduction with unprecedented precision at backward rapidities, far negative ...Feynman-x, using conventional detection techniques. At the nominal LHC energies, quarkonia can be studied in detail in p+p, p+d, and p+A collisions at sNN≃115 GeV and in Pb + p and Pb + A collisions at sNN≃72 GeV with luminosities roughly equivalent to that of the collider mode that is up to 20 fb−1 yr−1 in p+p and p+d collisions, up to 0.6 fb−1 yr−1 in p+A collisions, and up to 10 nb−1 yr−1 in Pb + A collisions. In this paper, we assess the feasibility of such studies by performing fast simulations using the performance of a LHCb-like detector.
We outline the case for heavy-ion-physics studies using the multi-TeV lead LHC beams in the fixed-target mode. After a brief contextual reminder, we detail the possible contributions of AFTER@LHC to ...heavy-ion physics with a specific emphasis on quarkonia. We then present performance simulations for a selection of observables. These show that
Υ
(
n
S
)
,
J
/
ψ
and
ψ
(
2
S
)
production in heavy-ion collisions can be studied in new energy and rapidity domains with the LHCb and ALICE detectors. We also discuss the relevance to analyse the Drell–Yan pair production in asymmetric nucleus–nucleus collisions to study the factorisation of the nuclear modification of partonic densities and of further quarkonium states to restore their status of golden probes of the quark–gluon plasma formation.
Thanks to its multi-TeV LHC proton and lead beams, the LHC complex allows one to perform the most energetic fixed-target experiments ever and to study with high precision pp, pd and pA collisions at ...sNN=115GeV and Pbp and PbA collisions at sNN=72GeV. We present a selection of feasibility studies for the production of quarkonia, open heavy-flavor mesons as well as light-flavor hadrons in pA and PbA collisions using the LHCb and ALICE detectors in a fixed-target mode.
We report on the opportunities for spin physics and Transverse-Momentum Dependent distribution (TMD) studies at a future multi-purpose fixed-target experiment using the proton or lead ion LHC beams ...extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic fixed-target experiments ever performed, opening new domains of particle and nuclear physics and complementing that of collider physics, in particular that of RHIC and the EIC projects. The luminosity achievable with AFTER@LHC using typical targets would surpass that of RHIC by more that 3 orders of magnitude in a similar energy region. In unpolarised proton-proton collisions, AFTER@LHC allows for measurements of TMDs such as the Boer-Mulders quark distributions, the distribution of unpolarised and linearly polarised gluons in unpolarised protons. Using the polarisation of hydrogen and nuclear targets, one can measure transverse single-spin asymmetries of quark and gluon sensitive probes, such as, respectively, Drell-Yan pair and quarkonium production. The fixed-target mode has the advantage to allow for measurements in the target-rapidity region, namely at large x↑ in the polarised nucleon. Overall, this allows for an ambitious spin program which we outline here.
J/ψ suppression induced by color screening of its constituent quarks was proposed 26 years ago as a signature of the formation of a quark gluon plasma in heavy-ion collisions. Recent results from ...ALICE in Pb–Pb collisions exhibit a smaller suppression with respect to previous measurements at the SPS and RHIC. The study of azimuthal anisotropy in particle production gives information on the collective hydrodynamic expansion at the early stage of the fireball, where the matter created in high-energy nuclear collisions is expected to be in a deconfined state. In particular, J/ψ elliptic flow v2 is important to test the degree of thermalization of heavy quarks. Together with the production yields, the elliptic flow is a powerful observable to address the question of suppression and regeneration of J/ψ in QGP. We present the first inclusive J/ψ elliptic flow measurement performed with the muon spectrometer of ALICE, in Pb–Pb collisions, at forward rapidity. Integrated and pT-differential v2 results are presented and a comparison with recent STAR results and with a parton transport model is also performed.
Front end electronics and first results of the ALICE V0 detector Zoccarato, Y.; Tromeur, W.; Aguilar, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2011, Letnik:
626
Journal Article
Recenzirano
This paper gives a detailed description of the acquisition and trigger electronics especially designed for the V0 detector of ALICE at LHC. A short presentation of the detector itself is given before ...the description of the Front End Electronics (FEE) system, which is completely embedded within the LHC environment as far as acquisition (DAQ), trigger (CTP), and detector control (DCS) are concerned. It is able to detect on-line coincident events and to achieve charge (with a precision of 0.6 pC) and time measurements (with a precision of 100
ps). It deploys quite a simple architecture. It is however totally programmable and fully non-standard in discriminating events coming from Beam–Beam interaction and Beam-Gas background. Finally, raw data collected from the first LHC colliding beams illustrate the performance of the system.
PDF
