1,283 research outputs found
Measurements of Λ+c production in pp collisions at √s = 7TeV with ALICE
A Large Ion Collider Experiment (ALICE) has been designed to
study the strongly interacting medium created in heavy-ion collisions at LHC energies, the Quark Gluon Plasma (QGP). Heavy quarks (charm and beauty), produced in the early stages of the collisions, are among the most powerful probes to study this state of matter. We report about the charmed baryon Λ+c measurement in pp collisions at √s = 7TeV with the ALICE experiment, through the reconstruction
of the decay channels Λ+c → pK−π+ and Λ+c → p ¯K 0 (and charge conjugates)
INFN What Next: Ultra-relativistic Heavy-Ion Collisions
This document was prepared by the community that is active in Italy, within
INFN (Istituto Nazionale di Fisica Nucleare), in the field of
ultra-relativistic heavy-ion collisions. The experimental study of the phase
diagram of strongly-interacting matter and of the Quark-Gluon Plasma (QGP)
deconfined state will proceed, in the next 10-15 years, along two directions:
the high-energy regime at RHIC and at the LHC, and the low-energy regime at
FAIR, NICA, SPS and RHIC. The Italian community is strongly involved in the
present and future programme of the ALICE experiment, the upgrade of which will
open, in the 2020s, a new phase of high-precision characterisation of the QGP
properties at the LHC. As a complement of this main activity, there is a
growing interest in a possible future experiment at the SPS, which would target
the search for the onset of deconfinement using dimuon measurements. On a
longer timescale, the community looks with interest at the ongoing studies and
discussions on a possible fixed-target programme using the LHC ion beams and on
the Future Circular Collider.Comment: 99 pages, 56 figure
Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider
Measurements of multi-particle azimuthal correlations (cumulants) for charged
particles in p-Pb and Pb-Pb collisions are presented. They help address the
question of whether there is evidence for global, flow-like, azimuthal
correlations in the p-Pb system. Comparisons are made to measurements from the
larger Pb-Pb system, where such evidence is established. In particular, the
second harmonic two-particle cumulants are found to decrease with multiplicity,
characteristic of a dominance of few-particle correlations in p-Pb collisions.
However, when a gap is placed to suppress such correlations,
the two-particle cumulants begin to rise at high-multiplicity, indicating the
presence of global azimuthal correlations. The Pb-Pb values are higher than the
p-Pb values at similar multiplicities. In both systems, the second harmonic
four-particle cumulants exhibit a transition from positive to negative values
when the multiplicity increases. The negative values allow for a measurement of
to be made, which is found to be higher in Pb-Pb collisions at
similar multiplicities. The second harmonic six-particle cumulants are also
found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find
which is indicative of a Bessel-Gaussian
function for the distribution. For very high-multiplicity Pb-Pb
collisions, we observe that the four- and six-particle cumulants become
consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and
Pb-Pb are measured. These are found to be similar for overlapping
multiplicities, when a gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87
Актуальні питання реалізації іпотечних зобов'язань в нотаріальному процесі
Стаття присвячена теоретичному дослідженню важливості використання існуючих механізмів превентивної юстиції та дієвості правозахисної функції нотаріату.
Доведено, що нотаріус як гарант превентивності правовідносин реалізує свої правозахисні функції не лише на стадії реалізації іпотечних зобовязань, шляхом вчинення виконавчого напису на борговому документі, а і на стадії узгодження та викладення всіх
істотних умов договору.
Ключові слова: нотаріат; правозахисна функція нотаріату; виконання зобовязань; превентивна юстиція.Статья посвящена теоретическому исследованию необходимости использования
существующих механизмов превентивной юстиции и действенности правозащитной
функции нотариата. Доказывается, что нотариус как гарант превентивности правоотношений реализует свои правозащитные функции не только на стадии реализации
ипотечных обязательств, в связи с совершением исполнительной надписи на долговом
документе, а и на стадии согласования и изложения всех существенных условий договора.
Ключевые слова: нотариат; правозащитная функция нотариату; исполнение обязательств; превентивная юстиция.This article is dedicated into theoretical research of importance in using special mechanism of prevention justitia and acting law defender functions of notoriety. It is argued that
notaries as a guaranty of prevention law relation realizes his law defender functions not only
on the stage of realization ipothek obligations, making performance inscription on the duty
document, but on the stage of consenting and stating all existence conditions of contract.
Key words: notoriety, law defender function of notaries, making obligations, prevention
justitia
Enhanced production of multi-strange hadrons in high-multiplicity proton-proton collisions
At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the quark-gluon plasma (QGP)(1). Such an exotic state of strongly interacting quantum chromodynamics matter is produced in the laboratory in heavy nuclei high-energy collisions, where an enhanced production of strange hadrons is observed(2-6). Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions(7), is more pronounced for multi-strange baryons. Several effects typical of heavy-ion phenomenology have been observed in high-multiplicity proton-proton (pp) collisions(8,9), but the enhanced production of multi-strange particles has not been reported so far. Here we present the first observation of strangeness enhancement in high-multiplicity proton-proton collisions. We find that the integrated yields of strange and multi-strange particles, relative to pions, increases significantly with the event charged-particle multiplicity. The measurements are in remarkable agreement with the p-Pb collision results(10,11), indicating that the phenomenon is related to the final system created in the collision. In high-multiplicity events strangeness production reaches values similar to those observed in Pb-Pb collisions, where a QGP is formed.Peer reviewe
Energy dependence and fluctuations of anisotropic flow in Pb-Pb collisions at √sNN=5.02 and 2.76 TeV
Measurements of anisotropic flow coefficients with two- and multi-particle cumulants
for inclusive charged particles in Pb-Pb collisions at sqrt(s_NN) = 5.02 and 2.76TeV
are reported in the pseudorapidity range |eta|< 0.8 and transverse momentum 0.2 < pT <
50 GeV/c. The full data sample collected by the ALICE detector in 2015 (2010), corresponding
to an integrated luminosity of 12.7 (2.0) ub^-1 in the centrality range 0-80%,
is analysed. Flow coefficients up to the sixth flow harmonic (v6) are reported and a detailed
comparison among results at the two energies is carried out. The pT dependence
of anisotropic flow coefficients and its evolution with respect to centrality and harmonic
number n are investigated. An approximate power-law scaling of the form vn(pT) ~ pT^(n/3)
is observed for all flow harmonics at low pT (0.2 < pT < 3 GeV/c). At the same time, the
ratios vn/vm^(n/m) are observed to be essentially independent of pT for most centralities up to
about pT = 10 GeV/c. Analysing the differences among higher-order cumulants of elliptic flow (v2),
which have different sensitivities to flow fluctuations, a measurement of the standardised
skewness of the event-by-event v2 distribution P(v2) is reported and constraints
on its higher moments are provided. The Elliptic Power distribution is used to parametrise
P(v2), extracting its parameters from fits to cumulants. The measurements are compared
to different model predictions in order to discriminate among initial-state models and to
constrain the temperature dependence of the shear viscosity to entropy-density ratio
Measurement of azimuthal correlations of D mesons with charged particles in pp collisions at √s=7 TeV and p-Pb collisions at √sNN=5.02 TeV
The azimuthal correlations of D mesons with charged particles were measured with the ALICE apparatus in pp collisions at root s = 7 TeV and p-Pb collisions at root sNN = 5.02 TeV at the Large Hadron Collider. D-0, D+, and D*+ mesons and their charge conjugates with transverse momentum 3 0.3 GeV/c. The yield of charged particles in the correlation peak induced by the jet containing the D meson and the peak width are compatible within uncertainties in the two collision systems. The data are described within uncertainties by Monte-Carlo simulations based on PYTHIA, POWHEG, and EPOS 3 event generators.Peer reviewe
Constraints on jet quenching in p-Pb collisions at root s(NN)=5.02 TeV measured by the event-activity dependence of semi-inclusive hadron-jet distributions
CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThe ALICE Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high-transverse momentum trigger hadron in p-Pb collisions at root s(NN) = 5.02TeV. Jets are reconstructed from charged-particle tracks using the anti-k(T) algorithm with resolution parameter R = 0.2 and 0.4. A data-driven statistical approach is used to correct the uncorrelated background jet yield. Recoil jet distributions are reported for jet transverse momentum 15 < p(T,jet)(ch) < 50 GeV/c and are compared in various intervals of p-Pb event activity, based on charged-particle multiplicity and zero-degree neutral energy in the forward (Pb-going) direction. The semi-inclusive observable is self-normalized and such comparisons do not require the interpretation of p-Pb event activity in terms of collision geometry, in contrast to inclusive jet observables. These measurements provide new constraints on the magnitude of jet quenching in small systems at the LHC. In p-Pb collisions with high event activity, the average medium-induced out-of-cone energy transport for jets with R = 0.4 and 15 < p(T,jet)(ch) < 50 GeV/c is measured to be less than 0.4 GeV/c at 90% confidence, which is over an order of magnitude smaller than a similar measurement for central Pb-Pb collisions at root s(NN) = 2.76 TeV. Comparison is made to theoretical calculations of jet quenching in small systems, and to inclusive jet measurements in p-Pb collisions selected by event activity at the LHC and in d-Au collisions at RHIC.78395113CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOSem informaçãoSem informaçãoSem informaçãoAgências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig
Global baryon number conservation encoded in net-proton fluctuations measured in Pb–Pb collisions at √sNN = 2.76 TeV
Experimental results are presented on event-by-event net-proton fluctuation measurements in Pb–Pb collisions at √SNN=2.76 TeV, recorded by the ALICE detector at the CERN LHC. These measurements have as their ultimate goal an experimental test of Lattice QCD (LQCD) predictions on second and higher order cumulants of net-baryon distributions to search for critical behavior near the QCD phase boundary. Before confronting them with LQCD predictions, account has to be taken of correlations stemming from baryon number conservation as well as fluctuations of participating nucleons. Both effects influence the experimental measurements and are usually not considered in theoretical calculations. For the first time, it is shown that event-by-event baryon number conservation leads to subtle long-range correlations arising from very early interactions in the collisions.publishedVersio
Inclusive J/ψ production at forward and backward rapidity in p-Pb collisions at √sNN=8.16 TeV
Inclusive J/psi production is studied in p-Pb interactions at a centre-of-mass
energy per nucleon-nucleon collision sqrt(s_NN) = 8.16TeV, using the ALICE detector at the
CERN LHC. The J/psi meson is reconstructed, via its decay to a muon pair, in the centre-of-mass
rapidity intervals 2.03 < ycms < 3.53 and -4.46 < ycms < -2.96, where positive
and negative ycms refer to the p-going and Pb-going direction, respectively. The transverse
momentum coverage is pT < 20 GeV/c. In this paper, ycms- and pT-differential cross
sections for inclusive J/psi production are presented, and the corresponding nuclear modification
factors RpPb are shown. Forward results show a suppression of the J/psi yield with
respect to pp collisions, concentrated in the region pT < 5 GeV/c. At backward rapidity
no significant suppression is observed. The results are compared to previous measurements
by ALICE in p-Pb collisions at sqrt(s_NN) = 5.02TeV and to theoretical calculations. Finally,
the ratios RFB between forward- and backward-ycms RpPb values are shown and discussed
- …