J. Barrette

• Professor at McGill University

This short paper shows that Rutherford first discussed in 1906, when he was at McGill, the possibility of determining the structure of the atom by measuring the diffusion of alpha particles in an experiment used to measure the retardation of alpha particles when passing through matter. The famous experiments of Geiger and Marsden that led to the di...

Predictions made in Albacete et al. [Int. J. Mod. Phys. E 22 (2013) 1330007] prior to the LHC p+Pb run at sNN=5 TeV are compared to currently available data. Some predictions shown here have been updated by including the same experimental cuts as the data. Some additional predictions are also presented, especially for quarkonia, that were provided...

Predictions made in Albacete et al. [J. Albacete et al., Int. J. Mod. Phys. E 22 (2013) 1330007.] prior to the LHC sNN=5 TeV are compared to the mostly final data from that run. Some predictions shown here have been updated by including the same experimental cuts as the data. Others are additions too late for the initial publication. Comparisons to...

Predictions made in Albacete {\it et al} prior to the LHC $p+$Pb run at $\sqrt{s_{NN}} = 5$ TeV are compared to currently available data. Some predictions shown here have been updated by including the same experimental cuts as the data. Some additional predictions are also presented, especially for quarkonia, that were provided to the experiments b...

Effects of strong longitudinal color electric fields, shadowing, and quenching on the production of prompt open charm mesons (D⁰, D⁺, D * + > , D s + > ) in central Pb + Pb collisions at s NN > = 2.76 TeV are investigated within the framework of the HIJING/B B ¯ > v2.0 model. We compute the nuclear modification factor RPbPbD, and s...

Predictions for charged hadron, identified light hadron, quarkonium, photon, jet and gauge bosons in p + Pb collisions at √sNN = 5 TeV are compiled and compared. When test run data are available, they are compared to the model predictions.

Predictions for charged hadron, identified light hadron, quarkonium, photon, jet and gauge bosons in p+Pb collisions at sqrt s_NN = 5 TeV are compiled and compared. When test run data are available, they are compared to the model predictions.

Collinear factorized perturbative quantum chromodynamics (pQCD) model predictions are compared for $p+{\rm Pb}$ at 5.02$A$ TeV to test nuclear shadowing of parton distribution at the Large Hadron Collider (LHC). The pseudorapidity distribution the nuclear modification factor (NMF), $R_{p{\rm Pb}}(y=0,p_T<20\;{\rm GeV}/{\it c}) = dn_{p{\rm Pb}} /(N_...

We use the framework of the HIJING/B\=B v2.0 model to simulate high-multiplicity (HM) $p+p$ collision events at the Large Hadron Collider (LHC) to study observables sensitive to possible collective phenomena, such as strong longitudinal color fields (SLCF) modeled by an enhanced string tension ($\kappa$). We focus on the hyperon/meson yield ratios...

Collinear factorized perturbative QCD model predictions are compared for p+Pb at 4.4A TeV to test nuclear shadowing of parton distribution at the Large Hadron Collider (LHC). The nuclear modification factor (NMF), R_{pPb}(y=0,p_T<20 GeV/c) = dn_{p Pb} /(N_{coll}(b)dn_{pp}), is computed with electron-nucleus (e+A) global fit with different nuclear s...

With the HIJING/BBbar v2.0 heavy ion event generator, we explore the phenomenological consequences of several high parton density dynamical effects predicted in central Pb+Pb collisions at the Large Hadron Collider (LHC) energies. These include (1) jet quenching due to parton energy loss (dE/dx), (2) strangeness and hyperon enhancement due to stron...

Gamma–gamma coincidence measurements, carried out with a 7.6 cm × 7.6 cm NaI(Tl) crystal and a 30 cm3 Ge–Li detector, have been performed to look for excited states in 144Nd higher than the known level at 1789 keV. These measurements definitely establish the existence of a level at 2093.11 keV and suggest the placing of another level at 2204.74 keV...

The γ-ray spectra accompanying the decay of 96gTc (4.3 d) and 96mTc (52 m), produced in the reactions 96Mo (p, n) 96Tc and 97Mo (p, 2n) 96Tc, have been studied with lithium-drifted Ge detectors.Gamma rays (relative intensities are in parentheses) of 314.2 ± 0.2 (2.4), 316.3 ± 0.2 (1.5), 434.8 ± 0.4 (0.8), 460.2 ± 0.4 (0.48), 568.9 ± 0.4 (.95), 778....

The γ-ray spectra resulting from the decay of the 94Tcm,g isomeric pair to the excited states of 94Mo have been investigated using Ge(Li) solid state detectors. Gamma rays (relative intensities are in parentheses) of 871.05(100); 993.19(2.35); 1196.4(0.80); 1522.1 (4.80); 1868.68(6.10); 2393.2(0.50); 2529.8(0.33); 2740.1(3.74); 3129.1(1.47); 3512.5...

The energies and relative intensities of the γ transitions following the 150Pm decay have been measured using high-resolution Ge(Li) detectors. A total of 140 γ rays was observed and 117 of these transitions could be traced to 34 levels in the 150Sm nucleus. A large amount of information on the structure of the 150Sm nucleus could be extracted by a...

Directional correlation measurements have been performed with two Ge(Li) counters on several γ rays in coincidence with the 121.78 and 334.31 keV γ transitions which de-excite the first 2+ levels in 152Sm and 152Gd, respectively. A total of 20 γ−γ directional correlations, 13 in the 152Sm nucleus and 7 in the 152Gd nucleus, was measured simultaneou...

The γ rays emitted in the decay of the 152Eum,g isomeric pair have been studied with the use of high-efficiency, high-resolution, solid-state detectors. These measurements together with Ge(Li)–Ge(Li) coincidence experiments revealed the existence of several new gamma transitions never previously reported. In all, 93 and 30 γ rays were observed in t...

We study the effect of strong longitudinal color fields (SCF) in p+p reactions up to Large Hadron Collider energies in the framework of the HIJING/BBbar v2.0 model that combines (collinear factorized) pQCD multiple minijet production with soft longitudinal string excitation and hadronization. The default vacuum string tension, kappa0 = 1 GeV/fm, is...

The effects of strong longitudinal color electric fields on the open charm production in nucleus-nucleus (A+A) collisions at 200A GeV are investigated within the framework of the HIJING/BB[over ] v2.0 model. A threefold increase of the effective string tension due to in-medium effects in A+A collisions results in a sizable ( approximately 60%-70%)...

Effects of strong longitudinal color electric fields (SCF) on the open charm production in nucleus-nucleus (A + A) collisions at 200A GeV are investigated within the framework of the HIJING-BBbar v2.0 model. A three fold increase of the effective string tension due to in medium effects in A + A collisions, results in a sizeable (60-70 percents) enh...

This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute 'Heavy Ion Collisions at the LHC - Last Call for Predictions', held from 14th May to 10th June 2007.

Strangeness and multi-strangeness particles production can be used to explore the initial transient field fluctuations in heavy ion collisions. We emphasize the role played by Junction anti-Junction (JJbar) loops and strong color electric fields (SCF) in these collisions. Transient field fluctuations of SCF on the baryon production in central (0-5%...

We investigate the energy dependence of hadron production and of stopping power based on HIJING/BBbar v2.0 model calculations. Pseudorapidity spectra and transverse momentum distributions for produced charged particles as well as net baryons (per pair of partcipants) and their rapidity loss are compared to data at RHIC and predictions for LHC energ...

The present status of the production of low-energy highly ionized beams by the 4-stage tandem accel-decel method is surveyed, and their use in three atomic physics experiments is summarized. The experiments are: the measurement of the charge state dependence of K-X-ray production in S+q-Ar collisions at 10 MeV, the impact-parameter dependence of qu...

The effect of fluctuations of strong color electric fields (SCF) on the baryon production in d+Au and Au+Au collisions at 200A GeV is studied in the framework of the HIJING/BB¯ v2.0 model. It is shown that the dynamics of the production process deviates considerably from calculations based on Schwinger-like estimates for homogeneous and constant co...

The effect of fluctuations of SCF on the baryon production in d+Au and Au+Au collisions at 200A GeV is studied in the framework of HIJING/BB v2.0 model. An increase of the string tension from kappa_0= 1 GeV/fm, to in medium mean values of 1.5 to 2.0 GeV/fm and 2.0 to 3.0 GeV/fm, for d+Au and Au+Au respectively, results in a consistent description o...

Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons...

Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons...

The effects of strong color electric fields (SCF) on the baryon production at RHIC are studied in the framework of HIJING/B\=B (v2.0) model. The particle species dependence of nuclear modification factors (NMF) are analyzed for Au+Au collisions at 200A GeV. A doubling of the string tension leading to a modification of the strangeness suppression ac...

A new version, v2.0, of the HIJING∕BB̅ Monte Carlo nuclear collision event generator is introduced in order to explore further the possible role of baryon junctions loops in the baryon-meson anomaly (2<pT<5 GeV∕c) observed in 200A GeV Au+Au reactions at RHIC. We show that junction loops with an enhanced intrinsic kT≈1 GeV∕c transverse momentum kick...

Transverse momentum spectra and yields of hadrons are measured by the PHENIX collaboration in Au+Au collisions at √sNN=130 GeV at the Relativistic Heavy Ion Collider. The time-of-flight resolution allows identification of pions to transverse momenta of 2 GeV∕c and protons and antiprotons to 4 GeV∕c. The yield of pions rises approximately linearly w...

We derive the phase space density of bosons from a general boson interferometry formula. We find that the phase space density is connected with the two-particle and the single-particle density distribution functions. If the boson density is large, the two-particle density distribution function cannot be expressed as a product of two single-particle...

PHENIX has measured the centrality dependence of charged hadron pT spectra from Au+Au collisions at GeV. The truncated mean pT decreases with centrality for pT>2 GeV/c, indicating an apparent reduction of the contribution from hard scattering to high pT hadron production. For central collisions the yield at high pT is shown to be suppressed compare...

The heavy ion collisions at collider energies were analyzed. The transverse energy and photons were measured independently in two different systems. The observed suppression indicated the absence of the expected hard scattering contribution.

The PHENIX detector is designed to perform a broad study of A–A, p–A, and p–p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of th...

We present the Pad Chamber detector system in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The three station system provides space points along each track in the spectrometer arms at mid-rapidity and covers a total area of . Its main functions are to provide the track coordinate along the be...

6 pages, RevTeX 3, 4 figures, 307 authors, submitted to Phys. Rev. Lett. on 11 April 2002. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (will be made) publicly available at http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.html

Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt [s(NN)]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values (v2) show significant sensitivit...

Recent data from relativistic heavy ion collider on rapidity and transverse momentum distributions of hadrons produced in ultrarelativistic reaction of both Au+Au and p+p are compared to predictions of the HIJING and RQMD models. The original default minijet scale p0=2 GeV∕c and energy loss, dE∕dx=2 GeV∕fm in HIJING lead to a too rapid growth of th...

We present results on the measurement of Lambda and Lambda(macro) production in Au+Au collisions at square root of (S (NN) = 130 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider. The transverse momentum spectra were measured for minimum bias and for the 5% most central events. The Lambda;/Lambda ratios are constant as a function...

Data from Au + Au interactions at sqrt[s(NN)]=130 GeV, obtained with the PHENIX detector at the Relativistic Heavy-Ion Collider, are used to investigate local net charge fluctuations among particles produced near midrapidity. According to recent suggestions, such fluctuations may carry information from the quark-gluon plasma. This analysis shows th...

Proton reaction cross-section measurements on various stable and neutron-rich nuclei (4,6He, 7–9Li, 9–11Be, 21–24F, 22–26Ne, 25–29Na and 29–32Mg) were performed via the attenuation method at intermediate energies (∼35–75A MeV) and using a cryogenic hydrogen target. The results are discussed in the framework of different approaches of the nucleon–nu...

Distributions of event-by-event fluctuations of the mean transverse momentum and mean transverse energy near mid-rapidity have been measured in Au+Au collisions at √sNN=130 GeV at the Relativistic Heavy-Ion Collider. By comparing the distributions to what is expected for statistically independent particle emission, the magnitude of nonstatistical f...

We present results on the measurement of Λ and Λ ¯ production in Au+Au collisions at s( NN)=130 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider. The transverse momentum spectra were measured for minimum bias and for the 5% most central events. The Λ ¯/Λ ratios are constant as a function of pT and the number of participants. The...

Identified pi(+/-), K(+/-), p, and (-)p transverse momentum spectra at midrapidity in sqrt[s(NN)] = 130 GeV Au+Au collisions were measured by the PHENIX experiment at RHIC as a function of collision centrality. Average transverse momenta increase with the number of participating nucleons in a similar way for all particle species. Within errors, all...

Two-pion correlations in square root[s(NN)] = 130 GeV Au+Au collisions at RHIC have been measured over a broad range of pair transverse momentum k(T) by the PHENIX experiment at RHIC. The k(T) dependent transverse radii are similar to results from heavy-ion collisions at square root[s(NN)] = 4.1, 4.9, and 17.3 GeV, whereas the longitudinal radius i...

Transverse momentum spectra of electrons from Au+Au collisions at square root[s(NN)] = 130 GeV have been measured at midrapidity by the PHENIX experiment at the Relativistic Heavy Ion Collider. The spectra show an excess above the background from photon conversions and light hadron decays. The electron signal is consistent with that expected from s...

Transverse momentum spectra of electrons from Au+Au collisions at sqrt[sNN] = 130 GeV have been measured at midrapidity by the PHENIX experiment at the Relativistic Heavy Ion Collider. The spectra show an excess above the background from photon conversions and light hadron decays. The electron signal is consistent with that expected from semilepton...

The PHENIX experiment is equipped with unique detectors for particle identification. The particle identification capabilities are demonstrated, based on the results from the RHIC Year-I Au+Au rub at sqrt(SNN) = 130 GeV.

The charged particle multiplicity and transverse energy are fundamental aspects of Heavy Ion collisions which PHENIX has measured in Au-Au collisions at a center-of-mass (C.M.S.) energy sqrt(SNN) = 130 GeV. Transverse energy is a multiparticle global observable related through the Bjorken relation to the maximum energy density achieved in the colli...

Transverse momentum spectra of charged particles have been measured by PHENIX in Au-Au collisions at sqrt(SNN) = 130 GeV. A systematic study of the distributions as a function of centrality is performed. Peripheral collisions results are similar to p-p while the most central collisions show a suppression of high momentum particles when compared to...

Proton reaction cross sections were measured on various stable and exotic nuclei, aiming at a better understanding of the potential for neutron rich nuclei.

Preliminary results of electron measurements at RHIC in Au+Au collisions at sqrt(SNN) = 130 A GeV are presented. Inclusive electron spectra are measured from a few hundred MeV/c to 4 GeV/c in transverse momentum. Inclusive photon spectra are measured by conversion methods from a few hundred MeV/c to 3 GeV/c.

Results from the PHENIX experiment for the first RHIC run with Au-Au collisions at roots(NN) = 130 GeV are presented. The systematic variation with centrality of charged particle multiplicity, transverse energy, elliptic flow, identified particle spectra and yield ratios, and production of charged particles and pi(0)'s at high transverse momenta ar...

This paper presents the results for the charged particle multiplicity and transverse energy distributions at mid-rapidity in Au+Au collisions at sqrt(SNN) = 130 GeV measured with the Phenix detector at RHIC. The values of dn_ch/d_eta_eta=0 and dE_T/d_eta_eta=0, analyzed as a function of centrality, show a consistent steady rise. For the 5% more cen...

Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 GeV/c<p(T)<5 GeV/c have been measured by the PHENIX experiment at RHIC in Au+Au collisions at root square[s(NN)] = 130 GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p+p collisions by the average number...

6 pages, RevTeX 3, 4 figures, 2 tables, 310 authors, submitted to Phys. Rev. Lett. on 17 April 2002. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (will be made) publicly available at http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.html

Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 GeV/c

The PHENIX experiment consists of a large detector system located at the newly commissioned relativistic heavy ion collider (RHIC) at the Brookhaven National Laboratory. The primary goal of the PHENIX experiment is to look for signatures of the QCD prediction of a deconfined high-energy-density phase of nuclear matter quark gluon plasma. PHENIX sta...

The charge and mass transition matrix elements of the neutron-rich isotopes 30,32Mg have been extracted from inelastic scattering on 208Pb and 12C targets at 32 A MeV. The measured inelastic cross sections for the first 2+ states were compared to coupled-channels calculations, which take into account the feeding from higher excited states. The meth...

The first measurement of energy produced transverse to the beam direction at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is presented. The midrapidity transverse energy density per participating nucleon rises steadily with the number of participants, closely paralleling the rise in charged-particle density, such that <E(T)...

The PHENIX experiment consists of a large detector system located at the newly commissioned relativistic heavy ion collider (RHIC) at the Brookhaven National Laboratory. The primary goal of the PHENIX experiment is to look for signatures of the QCD prediction of a deconfined high-energy-density phase of nuclear matter quark gluon plasma. PHENIX sta...

We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions at square root of [s(NN)] = 130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find dN(ch)/d eta(vertical line eta = 0) = 622+/-1(stat)+/-41(syst). The results, analyzed as a function of centrality, show a s...

The reaction cross section for the halo nucleus 6He on hydrogen has been measured at 36 MeV/nucleon using the transmission method and a value of σR=409±22 mb was obtained. A coherent analysis within a microscopic model of this result in conjunction with (p,p) and (p,n) angular distributions has allowed the interaction potential to be uniquely deter...

The charge and mass deformation parameters of the neutron-rich isotopes Mg-30,Mg-32 have been extracted from inelastic scattering at 32A MeV on Pb-208 and C-12 targets. The measured inelastic cross sections for the first 2(+) states were compared to coupled-channels calculations, which take into account the feeding from higher excited states. In th...

307 authors, 6 pages, 4 figures, 1 table, submitted to PRL 4/18/2001; revised version submitted to PRL 5/24/2001

New data on Λ production in Au+Au collisions at 11.5A GeV/c are presented. The measurements cover the rapidity range from y=2.0 to 3.5 and transverse momenta from pt=0.15 GeV/c to 1.5 GeV/c. The rapidity distributions, transverse momentum spectra, and azimuthal distributions are presented for different centralities of the collision. A strong positi...

We present proton and pion tranverse momentum spectra and rapidity distributions for Au+ Au collisions at 10.8 A GeV/c. The proton spectra exhibit collective transverse flow effects. Evidence of the influence of the Coulomb interaction from the fireball is found in the pion transverse momentum spectra. The data are compared with the predictions of...

Directed flow of antiprotons is studied in Au+Au collisions at a beam momentum of 11.5A GeV/c. It is shown that antiproton directed flow is anti-correlated to proton flow. The measured transverse momentum dependence of the antiproton flow is compared with predictions of the RQMD event generator.

Inclusive double differential multiplicities of deuterons, 3H, 3He, and 4He measured by E877 for 11.5A GeV/c Au+Au collisions at the Brookhaven’s Alternating Gradient Synchrotron (AGS) are presented. Light fragments at beam rapidity are measured for the first time at AGS energies. Beam rapidity deuteron and 4He yields and transverse slope parameter...

The E877 experiment was dedicated to the study of hadron distributions in Au+Au collisions at the AGS. Here, we will mainly present results from the analysis of the data obtained from the last data taking run, which took place in the fall of 1995 and recorded 46 millions Au+Au events at 11.5 AGeV/c. The improved experimental apparatus and large sta...

Anisotropy in the azimuthal distribution of the reaction products in heavy-ion collisions is an important observable which, in particular, contains information on the evolution and amplitude of the pressure gradient in the compressed nuclear matter formed in the collision and thus on its equation of state. It was first observed in ultra-relativisti...

A new concept for two-dimensional position readout of wire chambers is described. The basic idea is to use a cathode segmented into small pixels that are read out in specific groups (pads). The electronics is mounted on the outer face of the chamber with a chip-on-board technique, pushing the material thickness to a minimum. The system described he...

Anisotropy in the azimuthal distribution of the reaction products in heavy-ion collisions is an important observable which, in particular, contains information on the evolution and amplitude of the pressure gradient in the compressed nuclear matter formed in the collision and thus on its equation of state. It was first observed in ultra-relativisti...

Two-proton correlation functions have been measured in Si+Pb collisions at 14.6A GeV/c and Au+Au collisions at 11.5{ital A} GeV/{ital c} by the E814/E877 Collaboration. Data are compared with predictions of the transport model RQMD and the source size is inferred from this comparison. Our analysis shows that, for both reactions, the characteristic...

Two-proton correlation functions have been measured in Si+Pb collisions at 14.6A GeV/c and Au+Au collisions at 11.5A GeV/c by the E814/E877 Collaboration. Data are compared with predictions of the transport model RQMD and the source size is inferred from this comparison. Our analysis shows that, for both reactions, the characteristic size of the sy...

Two-proton correlation functions have been measured in Si+Pb collisions at 14.6A GeV/c and Au+Au collisions at 11.5A GeV/c by the E814/E877 Collaboration. Data are compared with predictions of the transport model RQMD and the source size is inferred from this comparison. Our analysis shows that, for both reactions, the characteristic size of the sy...

Directed flow of deuterons, tritons, 3He, and 4He is studied in Au+Au collisions at a beam momentum of 10.8AGeV/c. Flow of all particles is analyzed as a function of transverse momentum for different centralities of the collision. The directed flow signal, v1(pt), is found to increase with particle mass. This mass dependence is strongest in the pro...

The 12C(16O, alpha )24Mg reaction has been used to study states in 24Mg at excitation energies up to 27 MeV. Total widths have been measured for 34 states. Alpha-branching ratios and alpha - alpha angular correlations have been measured for 12 states above 19.5 MeV. Candidates for 10+ and 12+ states in 24Mg are deduced from a comparison with shell-...

The charge-exchange reaction p(6He, 6Li)n is studied in reverse kinematics with a secondary 6He beam at 41.6 MeV/nucleon. The transition connecting the ground state of 6He to its isobaric analog state in 6Li has been measured and analyzed in the context of a microscopic calculation. The angular distribution is shown to be sensitive to the nuclear i...

A 3D electrothermal model for high-power HBTs is presented. This non-linear model, based on the finite difference method, computes the temperature distribution under static bias conditions for multifinger HBTs. The model takes into account emitter ballast resistance, thermal shunt design and the non-linear temperature dependence of substrate therma...

The authors report for the first time a time-domain analysis of thermal instability in multifinger heterojunction bipolar transistors (HBT's). This is based on a transient quasi-three-dimensional (3-D) electrothermal model that selfconsistently solves the thermal and electrical equations. This model is designed to evaluate the thermal time constant...

In this article recent results of the E877 collaboration are presented. They include double differential multiplicities and rapidity densities of hadrons produced in Au+Au collisions at 11 AgeV/c, two-particle correlations of like and unlike particles, as well as some recent results on particle flow.