Intramuscular vaccination of Atlantic lumpfish (Cyclopterus lumpus L.) induces inflammatory reactions and local immunoglobulin M production at the vaccine administration site

Atlantic lumpfish were vaccinated by intramuscular (im) or intraperitoneal (ip) injection with a multivalent oil‐based vaccine, while control fish were injected with phosphate‐buffered saline. Four lumpfish per group were sampled for skin/muscle and head kidney tissue at 0, 2, 7, 21 and 42 days post‐immunization (dpi) for histopathology and immunohistochemistry (IHC). Gene expressions of secretory IgM, membrane‐bound IgM, IgD, TCRα, CD3ε and MHC class IIβ were studied in tissues by using qPCR. Im. vaccinated fish showed vaccine‐induced inflammation with formation of granulomas and increasing number of eosinophilic granulocyte‐like cells over time. On IHC sections, we observed diffuse intercellular staining of secretory IgM at the injection site at 2 dpi, while IgM + cells appeared in small numbers at 21 and 42 dpi. Skin/muscle samples from im. vaccinated fish demonstrated an increase in gene expression of IgM mRNA (secretory and membrane‐bound) at 21 and 42 dpi and small changes for other genes. Our results indicated that im. vaccination of lumpfish induced local IgM production at the vaccine injection site, with no apparent proliferation of IgM + cells. Eosinophilic granulocyte‐like cells appeared shortly after im. injection and increased in numbers as the inflammation progressed.publishedVersio

Jet-Like Correlations with Direct-Photon and Neutral-Pion Triggers at √\u3cem\u3e\u3csup\u3eS\u3c/sup\u3e\u3csub\u3eNN\u3c/sub\u3e\u3c/em\u3e = 200 GeV

Azimuthal correlations of charged hadrons with direct-photon (γdir) and neutral-pion (π0) trigger particles are analyzed in central Au+Au and minimum-bias p+p collisions at in the STAR experiment. The charged-hadron per-trigger yields at mid-rapidity from central Au+Au collisions are compared with p+p collisions to quantify the suppression in Au+Au collisions. The suppression of the away-side associated-particle yields per γdir trigger is independent of the transverse momentum of the trigger particle (ptrigT), whereas the suppression is smaller at low transverse momentum of the associated charged hadrons (passocT). Within uncertainty, similar levels of suppression are observed for γdir and π0 triggers as a function of zT (passocT / ptrigT). The results are compared with energy-loss-inspired theoretical model predictions. Our studies support previous conclusions that the lost energy reappears predominantly at low transverse momentum, regardless of the trigger energy

Jet-Hadron Correlations in √\u3csup\u3es\u3c/sup\u3eNN=200 GeV \u3cem\u3ep\u3c/em\u3e+\u3cem\u3ep\u3c/em\u3e and Central Au+Au Collisions

Azimuthal angular correlations of charged hadrons with respect to the axis of a reconstructed (trigger) jet in Au+Au and p+p collisions at √sNN=200  GeV in STAR are presented. The trigger jet population in Au+Au collisions is biased toward jets that have not interacted with the medium, allowing easier matching of jet energies between Au+Au and p+p collisions while enhancing medium effects on the recoil jet. The associated hadron yield of the recoil jet is significantly suppressed at high transverse momentum (passocT) and enhanced at low passocT in 0%–20% central Au+Au collisions compared to p+p collisions, which is indicative of medium-induced parton energy loss in ultrarelativistic heavy-ion collisions

Energy Dependence of Acceptance-Corrected Dielectron Excess Mass Spectrum at Mid-Rapidity in Au + Au Collisions at √\u3csup\u3es\u3c/sup\u3eNN = 19.6 and 200 GeV

The acceptance-corrected dielectron excess mass spectra, where the known hadronic sources have been subtracted from the inclusive dielectron mass spectra, are reported for the first time at mid-rapidity ∣yee∣+ Au collisions at √sNN = 19.6 and 200 GeV. The excess mass spectra are consistently described by a model calculation with a broadened ρ spectral function for Mee \u3c 1.1 GeV/c2. The integrated dielectron excess yield at √sNN = 19.6 GeV for 0.4 \u3c Mee \u3c 0.75 GeV/c2, normalized to the charged particle multiplicity at mid-rapidity, has a value similar to that in ln+ln collisions at √sNN = 17.3 GeV. For √sNN = 200 GeV, the normalized excess yield in central collisions is higher than that at √sNN = 17.3 GeV and increases from peripheral to central collisions. These measurements indicate that the lifetime of the hot, dense medium created in central Au + Au collisions at √sNN = 200 GeV is longer than those in peripheral collisions and at lower energies

Di-Hadron Correlations with Identified Leading Hadrons in 200 GeV Au + Au and d + Au Collisions at STAR

The STAR Collaborationpresents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au+Au and minimum-bias d+Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au + Au data with respect to the d + Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization

Energy Dependence of \u3cem\u3eKπ\u3c/em\u3e, \u3cem\u3epπ\u3c/em\u3e, and \u3cem\u3eKp\u3c/em\u3e Fluctuations in Au + Au Collisions from √\u3cem\u3e\u3csup\u3es\u3c/sup\u3eNN\u3c/em\u3e=7.7 to 200 GeV

A search for the quantum chromodynamics (QCD) critical point was performed by the STAR experiment at the BNL Relativistic Heavy Ion Collider, using dynamical fluctuations of unlike particle pairs. Heavy ion collisions were studied over a large range of collision energies with homogeneous acceptance and excellent particle identification, covering a significant range in the QCD phase diagram where a critical point may be located. Dynamical Kπ, pπ, and Kp fluctuations as measured by the STAR experiment in central 0–5% Au + Au collisions from center-of-mass collision energies √sNN=7.7 to 200 GeV are presented. The observable νdyn was used to quantify the magnitude of the dynamical fluctuations in event-by-event measurements of the Kπ, pπ, and Kp pairs. The energy dependences of these fluctuations from central 0–5% Au + Au collisions all demonstrate a smooth evolution with collision energy

Observation of Transverse Spin-Dependent Azimuthal Correlations of Charged Pion Pairs in \u3cem\u3ep\u3c/em\u3e\u3csup\u3e↑\u3c/sup\u3e+\u3cem\u3ep\u3c/em\u3e at √\u3cem\u3es\u3c/em\u3e=200 GeV

We report the observation of transverse polarization-dependent azimuthal correlations in charged pion pair production with the STAR experiment in p↑+p collisions at RHIC. These correlations directly probe quark transversity distributions. We measure signals in excess of 5 standard deviations at high transverse momenta, at high pseudorapidities η\u3e0.5, and for pair masses around the mass of the ρ meson. This is the first direct transversity measurement in p+p collisions

Azimuthal Anisotropy in U+U and Au+Au Collisions at RHIC

Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2{2} and v2{4}, for charged hadrons from U+U collisions at √sNN=193  GeV and Au+Au collisions at √sNN=200  GeV. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v2{2} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. We also show that v2 vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions

Effect of Event Selection on Jetlike Correlation Measurement in \u3cem\u3ed\u3c/em\u3e+Au Collisions at √\u3csup\u3es\u3c/sup\u3eNN=200 GeV

Dihadron correlations are analyzed in √sNN = 200 GeV d + Au collisions classified by forward charged particle multiplicity and zero-degree neutral energy in the Au-beam direction. It is found that the jetlike correlated yield increases with the event multiplicity. After taking into account this dependence, the non-jet contribution on the away side is minimal, leaving little room for a back-to-back ridge in these collisions

Measurements of Dielectron Production in Au + Au Collisions at √\u3cem\u3es\u3csub\u3eNN\u3c/sub\u3e\u3c/em\u3e = 200 GeV from the STAR Experiment

We report on measurements of dielectron (e+e−) production in Au + Au collisions at a center-of-mass energy of 200 GeV per nucleon-nucleon pair using the STAR detector at BNL Relativistic Heavy Ion Collider. Systematic measurements of the dielectron yield as a function of transverse momentum (pT) and collision centrality show an enhancement compared to a cocktail simulation of hadronic sources in the low invariant-mass region (Mee \u3c 1 GeV/c2). This enhancement cannot be reproduced by the ρ-meson vacuum spectral function. In minimumbias collisions, in the invariant-mass range of 0.30–0.76 GeV/c2, integrated over the full pT acceptance, the enhancement factor is 1.76 ± 0.06 (stat.) ± 0.26 (sys.) ± 0.29 (cocktail). The enhancement factor exhibits weak centrality and pT dependence in STAR’s accessible kinematic regions,while the excess yield in this invariant-mass region as a function of the number of participating nucleons follows a power-law shape with a power of 1.44 ± 0.10. Models that assume an in-medium broadening of the ρ-meson spectral function consistently describe the observed excess in these measurements. Additionally, we report on measurements of ω- and φ-meson production through their e+e− decay channel. These measurements show good agreement with Tsallis blast-wave model predictions, as well as, in the case of the φ meson, results through its K+K− decay channel. In the intermediate invariant-mass region (1.1\u3cMee \u3c 3 GeV/c2), we investigate the spectral shapes from different collision centralities. Physics implications for possible in-medium modification of charmed hadron production and other physics sources are discussed