The Study of Noncollectivity by the Forward-Backward Multiplicity Correlation Function

We propose a forward-backward multiplicity correlation function $C^N_{FB}$, which is experimentally accessible, to measure the noncollectivity contribution. We find that $C^N_{FB}$ is sensitive to the jet contribution for the particle-rich case. Surprisingly, it will automatically decrease for the particle-rare case. Our study indicates that similar decreasing trend observed previously is mainly driven by particle scarcity instead of jets. The function is studied in Au+Au collision at $\sqrt{s_{NN}}=200$ GeV with a multiphase transport model (AMPT). We find that the jet fraction is about 10% at transverse momentum ($p_T$) around 2.5 GeV/$c$ and reaches up to 30% at 3.5 GeV/$c$. The implication of this study in the investigation of the noncollectivity contribution in elliptic anisotropy parameter $v_2$ is also discussed.Comment: 5 pages, 4 figure

Azimuthal distributions of radial momentum and velocity in relativistic heavy ion collisions

Azimuthal distributions of radial (transverse) momentum, mean radial momentum, and mean radial velocity of final state particles are suggested for relativistic heavy ion collisions. Using transport model AMPT with string melting, these distributions for Au + Au collisions at 200 GeV are presented and studied. It is demonstrated that the distribution of total radial momentum is more sensitive to the anisotropic expansion, as the anisotropies of final state particles and their associated transverse momentums are both counted in the measure. The mean radial velocity distribution is compared with the radial {\deg}ow velocity. The thermal motion contributes an isotropic constant to mean radial velocity

Detecting the long-distance structure of the X(3872)

We study the decay within a molecular picture for the state. This decay mode is more sensitive to the long-distance structure of the resonance than its and decays, which are mainly controlled by the details of the wave function at short distances. We show that the final state interaction can be important, and that a precise measurement of this partial decay width can provide valuable information on the interaction strength between the charm mesons

Molecular Genetic Markers and Clinical Characteristics of Essential Thrombocythemia

Background & Aims. The presence of different molecular genetic markers of clonality (mutations in JAK2, MPL, CALR) or their absence (triple negative status, TN) in essential thrombocythemia (ET) indicates a biological heterogeneity of the disease and can determine its clinical forms. The aim was to evaluate the association of molecular genetic markers with the clinical form and the prognosis of ET. Materials & Methods. We analyzed the data of 240 patients with ET at the age of 20–91 years (median age 58.7 years), who were observed in the Russian Research Institute of Hematology and Transfusiology from 1999 to 2016 (median observation period 37.2 months). Results. The JAK2V617F (JAK2+) mutation was found in 182 (75.9 %) of 240 patients. CALR (CALR+) mutations were found in 30 (12.5 %): type 1 (CALR1+) mutations in 13/30 (43.3 %) and type 2 (CALR2+) in 17/30 (56.7 %). MPL (MPL+) mutations were found in only 2 (0.8 %) of 240 patients. None of the mutations were detected in 26 (10.8 %) of 240 patients (TN status). Significantly higher platelet counts were observed in CALR1+ and CALR2+ subgroups during the primary diagnosis of ET compared with JAK2+ and TN groups. The mean platelet counts were 1252 × 109/L for CALR2+ and 1079 × 109/L for CALR1+ vs 841 × 109/L (p < 0.001; p = 0.06) and 775 × 109/L (p < 0.001; p = 0.04) for JAK2+ and TN, respectively. Thrombosis was diagnosed in 50 (27.4 %) of 182 patients of the JAK2+ subgroup, in 8 (30.7 %) of the 26 patients of the TN subgroup, and in 2 (18.2 %) of 11 patients of the CALR1+ subgroup. No thrombosis was found in the CALR2+ and MPL+ subgroups (p < 0.001). In general, the CALR1+ status was characterized as the most favorable in terms of prognosis (5-year overall survival rate of 100 %), compared to the least favorable TN status (5-year overall survival rate of 85 %). Conclusion. Mutations in the CALR gene were characterized by a more favorable prognosis in comparison with JAK2+ and TN, as well as a decrease in the risk and frequency of thrombosis, despite higher platelet counts. TN-status of ET was associated with unfavorable prognosis

QCD and strongly coupled gauge theories : challenges and perspectives

We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

First measurement of the |t|-dependence of coherent J/ψ photonuclear production

The first measurement of the cross section for coherent J/ψ photoproduction as a function of |t|, the square of the momentum transferred between the incoming and outgoing target nucleus, is presented. The data were measured with the ALICE detector in ultra-peripheral Pb–Pb collisions at a centre-of-mass energy per nucleon pair sNN=5.02TeV with the J/ψ produced in the central rapidity region |y|<0.8, which corresponds to the small Bjorken-x range (0.3−1.4)×10−3. The measured |t|-dependence is not described by computations based only on the Pb nuclear form factor, while the photonuclear cross section is better reproduced by models including shadowing according to the leading-twist approximation, or gluon-saturation effects from the impact-parameter dependent Balitsky–Kovchegov equation. These new results are therefore a valid tool to constrain the relevant model parameters and to investigate the transverse gluonic structure at very low Bjorken-x.publishedVersio

Resolving the strange behavior of extraterrestrial potassium in the upper atmosphere

It has been known since the 1960s that the layers of Na and K atoms, which occur between 80 and 105 km in the Earth's atmosphere as a result of meteoric ablation, exhibit completely different seasonal behavior. In the extratropics Na varies annually, with a pronounced wintertime maximum and summertime minimum. However, K varies semiannually with a small summertime maximum and minima at the equinoxes. This contrasting behavior has never been satisfactorily explained. Here we use a combination of electronic structure and chemical kinetic rate theory to determine two key differences in the chemistries of K and Na. First, the neutralization of K+ ions is only favored at low temperatures during summer. Second, cycling between K and its major neutral reservoir KHCO3 is essentially temperature independent. A whole atmosphere model incorporating this new chemistry, together with a meteor input function, now correctly predicts the seasonal behavior of the K layer

Particle identification in ALICE : a Bayesian approach

Peer reviewe