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

Constraining the magnitude of the chiral magnetic effect with event shape engineering in Pb-Pb collisions at root s(NN)=2.76 TeV

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOIn ultrarelativistic heavy-ion collisions, the event-by-event variation of the elliptic flow v(2) reflects fluctuations in the shape of the initial state of the system. This allows to select events with the same centrality but different initial geometry. This selection technique, Event Shape Engineering, has been used in the analysis of charge-dependent two-and three-particle correlations in Pb-Pb collisions at root s(NN) = 2.76 TeV. The two-particle correlator < cos(phi(alpha) - phi(ss))gt;, calculated for different combinations of charges alpha and beta, is almost independent of v(2) (for a given centrality), while the three-particle correlator < cos(phi(alpha) + phi(beta) - 2 Psi(2))gt; scales almost linearly both with the event v(2) and charged-particle pseudorapidity density. The charge dependence of the three-particle correlator is often interpreted as evidence for the Chiral Magnetic Effect (CME), a parity violating effect of the strong interaction. However, its measured dependence on v(2) points to a large non-CME contribution to the correlator. Comparing the results with Monte Carlo calculations including a magnetic field due to the spectators, the upper limit of the CME signal contribution to the three-particle correlator in the 10-50% centrality interval is found to be 26-33% at 95% confidence level.777151162CNPQ - 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

Production of deuterons, tritons, He-3 nuclei, and their antinuclei in pp collisions at root s=0.9, 2.76, and 7 TeV

Invariant differential yields of deuterons and antideuterons in pp collisions at root s = 0.9, 2.76 and 7 TeV and the yields of tritons, He-3 nuclei, and their antinuclei at root s = 7 TeV have been measured with the ALICE detector at the CERN Large Hadron Collider. The measurements cover a wide transverse momentum (p(T)) range in the rapidity interval vertical bar y vertical bar <0.5, extending both the energy and the pT reach of previous measurements up to 3 GeV/c for A = 2 and 6 GeV/c for A = 3. The coalescence parameters of (anti) deuterons and 3 He nuclei exhibit an increasing trend with pT and are found to be compatible with measurements in pA collisions at low p(T) and lower energies. The integrated yields decrease by a factor of about 1000 for each increase of the mass number with one (anti) nucleon. Furthermore, the deuteron-to-proton ratio is reported as a function of the average charged particle multiplicity at different center-of-mass energies.Peer reviewe

Longitudinal asymmetry and its effect on pseudorapidity distributions in Pb-Pb collisions at root s(NN)=2.76 TeV

First results on the longitudinal asymmetry and its effect on the pseudorapidity distributions in Pb-Pb collisions at root s(NN) = 2.76 TeV at the Large Hadron Collider are obtained with the ALICE detector. The longitudinal asymmetry arises because of an unequal number of participating nucleons from the two colliding nuclei, and is estimated for each event by measuring the energy in the forward neutron-Zero-Degree-Calorimeters (ZNs). The effect of the longitudinal asymmetry is measured on the pseudorapidity distributions of charged particles in the regions vertical bar eta vertical bar < 0.9, 2.8 < eta < 5.1 and -3.7 < eta < -1.7 by taking the ratio of the pseudorapidity distributions from events corresponding to different regions of asymmetry. The coefficients of a polynomial fit to the ratio characterise the effect of the asymmetry. A Monte Carlo simulation using a Glauber model for the colliding nuclei is tuned to reproduce the spectrum in the ZNs and provides a relation between the measurable longitudinal asymmetry and the shift in the rapidity (y(0)) of the participant zone formed by the unequal number of participating nucleons. The dependence of the coefficient of the linear term in the polynomial expansion, c(1), on the mean value of y(0) is investigated.Peer reviewe

First measurement of Ξc0 production in pp collisions at s=7 TeV

The production of the charm-strange baryon Csi0c is measured for the first time at the LHC via its semileptonic decay into e+Csi-νe in pp collisions at sqrt(s) = 7 TeV with the ALICE detector. The transverse momentum (pT) differential cross section multiplied by the branching ratio is presented in the interval 1 &lt; pT &lt; 8 GeV/c at mid-rapidity, |y| &lt; 0.5. The transverse momentum dependence of the Csi0c baryon production relative to the D0 meson production is compared to predictions of event generators with various tunes of the hadronisation mechanism, which are found to underestimate the measured cross- section ratio.The production of the charm-strange baryon Csi0c is measured for the first time at the LHC via its semileptonic decay into e+Csi-νe in pp collisions at sqrt(s) = 7 TeV with the ALICE detector. The transverse momentum (pT) differential cross section multiplied by the branching ratio is presented in the interval 1 &lt; pT &lt; 8 GeV/c at mid-rapidity, |y| &lt; 0.5. The transverse momentum dependence of the Csi0c baryon production relative to the D0 meson production is compared to predictions of event generators with various tunes of the hadronisation mechanism, which are found to underestimate the measured cross- section ratio

Measurement of Z(0)-boson production at large rapidities in Pb-Pb collisions at root s(NN)=5.02 TeV

The production of Z(0) bosons at large rapidities in Pb-Pb collisions at root s(NN) = 5.02 TeV is reported. Z(0) candidates are reconstructed in the dimuon decay channel (Z(0) -> mu(+) mu(-)), based on muons selected with pseudo-rapidity -4.0 20 GeV/c. The invariant yield and the nuclear modification factor, RAA, are presented as a function of rapidity and collision centrality. The value of R-AA for the 0-20% central Pb-Pb collisions is 0.67 +/- 0.11(stat.) +/- 0.03 (syst.) f 0.06(corr. syst.), exhibiting a deviation of 2.6 sigma from unity. The results are well-described by calculations that include nuclear modifications of the parton distribution functions, while the predictions using vacuum PDFs deviate from data by 2.3 sigma in the 0-90% centrality class and by 3 sigma in the 0-20% central collisions. (C) 2018 The Author(s). Published by Elsevier B.V.Peer reviewe

Transverse momentum spectra and nuclear modification factors of charged particles in pp, p-Pb and Pb-Pb collisions at the LHC

CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOWe report the measured transverse momentum (pT) spectra of primary charged particles from pp, p-Pb and Pb-Pb collisions at a center-of-mass energy p sNN = 5 : 02TeV in the kinematic range of 0 : 15 < pT < 50 GeV/c and jj < 0 : 8. A signi fi cant improvement of systematic uncertainties motivated the reanalysis of data in pp and Pb-Pb collisions at p sNN = 2 : 76TeV, as well as in p-Pb collisions at p sNN = 5 : 02TeV, which is also presented. Spectra from Pb-Pb collisions are presented in nine centrality intervals and are compared to a reference spectrum from pp collisions scaled by the number of binary nucleon-nucleon collisions. For central collisions, the pT spectra are suppressed by more than a factor of 7 around 6-7 GeV/c with a signi fi cant reduction in suppression towards higher momenta up to 30 GeV/c. The nuclear modi fi cation factor RpPb, constructed from the pp and p-Pb spectra measured at the same collision energy, is consistent with unity above 8 GeV/c. While the spectra in both pp and Pb-Pb collisions are substantially harder at p sNN = 5 : 02TeV compared to 2.76TeV, the nuclear modi fi cation factors show no signi fi cant collision energy dependence. The obtained results should provide further constraints on the parton energy loss calculations to determine the transport properties of the hot and dense QCD matter.11133CNPQ - 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 PAULOAgências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig

J/psi Elliptic Flow in Pb-Pb Collisions at root s(NN)=5.02 TeV

We report a precise measurement of the J/ψ elliptic flow in Pb-Pb collisions at √sNN=5.02 TeV with the ALICE detector at the LHC. The J/ψ mesons are reconstructed at midrapidity (|y|<0.9) in the dielectron decay channel and at forward rapidity (2.5<y<4.0) in the dimuon channel, both down to zero transverse momentum. At forward rapidity, the elliptic flow v2 of the J/ψ is studied as a function of the transverse momentum and centrality. A positive v2 is observed in the transverse momentum range 2<pT<8  GeV/c in the three centrality classes studied and confirms with higher statistics our earlier results at √sNN=2.76 TeV in semicentral collisions. At midrapidity, the J/ψ  v2 is investigated as a function of the transverse momentum in semicentral collisions and found to be in agreement with the measurements at forward rapidity. These results are compared to transport model calculations. The comparison supports the idea that at low pT the elliptic flow of the J/ψ originates from the thermalization of charm quarks in the deconfined medium but suggests that additional mechanisms might be missing in the models

LATEST 10 YEARS IN THE STUDY OF FLORA OF SURA RIVER BASIN

The report presents information on the development of floristic studies of the Sura River basin, a right-bank tributary of the Volga. The basin stretches from north to south, it is extremely interesting in biogeographical terms. The results of long-term study of the flora of the basin were summed up in 2006. But the floristic studies in the basin area were continued in the framework of studying the flora of the northwest of the Volga Upland. As a result, new materials were obtained. On the territory of the basin after 2006, such rare species of aboriginal flora as Schoenus ferrugineus L., *Matthiola fragrans (Fisch.) Bunge, Caragana frutex (L.) C. Koch, Oxytropis baschkiriensis Knjaz., Polygala amarella Crantz, ( L.) Hornem., Aster alpinus L. In recent years many new alien plants have been noted in the Sura Basin: Adonis aestivalis L., Amaranthus powellii Wats., Solanum physalifolium Rusby, S. shultesii Opiz, Artemisia macrocephala Jacq. ex Bess. and etc.Работа частично выполнена в рамках государственного задания согласно тематическому плану Ботанического сада Уральского отделения Российской академии наук (гос. задание №007–00077–18–00), тема «Исследование и охрана фенотипического и генетического разнообразия флоры и растительности России» (регистрационный № НИОКТР АААА–А17–117072810011–1)