Statistical properties of the energy levels in the axial channeling quantum theory

The energy of transversal motion of relativistic charged particles in the uniform potential of atomic strings of a crystal could be quantized. The energy levels of electrons axially channeled in the system of parallel [110] atomic strings of silicon crystal are obtained. The distribution of distances between neighbor energy levels in the quasi-classical region, where the levels density is high, is agreed with quantum chaos theory predictions.При каналировании быстрых заряженных частиц в кристалле может иметь место квантование энергии поперечного движения частицы в непрерывных потенциалах атомных цепочек. В предлагаемой работе найдены уровни энергии электронов, движущихся в режиме аксиального каналирования в системе параллельных атомных цепочек (на примере цепочек [110] кристалла кремния). Показано, что распределение межуровневых расстояний в квазиклассической области, где плотность уровней велика, согласуется с предсказаниями теории квантового хаоса.При каналюваннi швидких заряджених частинок у кристалi може бути наявним квантування енергiї поперечного руху в неперервних потенцiалах атомних ланцюжкiв. У запропонованiй роботi знайденi рiвнi енергiї електронiв, якi рухаються у режимi аксиального каналювання у системi паралельних атомних ланцюжкiв (на прикладi ланцюжкiв [110] кристала кремнiя). Показано, що розподiл мiжрiвневих вiдстанiв у квазикласичнiй областi, де щiльнiсть рiвнiв є великою, узгоджується з передбаченнями теорiї квантового хаосу

Measurement of the tensor analyzing power T20 in the dd->^3Hen and dd->^3Hp at intermediate energies and at zero degree

The data on the tensor analyzing power T20 in the dd->^3Hen and dd-> ^3Hp reactions at 140, 200 and 270 MeV of the deuteron kinetic energy and at zero degree obtained at RIKEN Accelerator Research Facility are presented. The observed positive sign of T20 clearly demonstrates the sensitivity to the D/S wave ratios in the ^3He and ^3H in the energy domain of the measurements. The T20 data for the ^3He-n and ^3H-p channels are in agreement within experimental accuracy.Comment: 9 pages, 3 figures, submitted in Phys.Lett.

Measurement of the vector and tensor analyzing powers for dp- elastic scattering at 880 MeV

The vector Ay and tensor analyzing powers Ayy and Axx for dp- elastic scattering were measured at Td = 880 MeV over the c.m. angular range from 60 to 140 degrees at the JINR Nuclotron. The data are compared with predictions of different theoretical models based on the use of nucleon-nucleon forces only. The observed discrepancies of the measured analyzing powers from the calculations require the consideration of additional mechanisms.Comment: 5 pages,3 figure

Measurement of Bottom versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p+p Collisions at sqrt(s)=200 GeV

The momentum distribution of electrons from semi-leptonic decays of charm and bottom for mid-rapidity |y|<0.35 in p+p collisions at sqrt(s)=200 GeV is measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) over the transverse momentum range 2 < p_T < 7 GeV/c. The ratio of the yield of electrons from bottom to that from charm is presented. The ratio is determined using partial D/D^bar --> e^{+/-} K^{-/+} X (K unidentified) reconstruction. It is found that the yield of electrons from bottom becomes significant above 4 GeV/c in p_T. A fixed-order-plus-next-to-leading-log (FONLL) perturbative quantum chromodynamics (pQCD) calculation agrees with the data within the theoretical and experimental uncertainties. The extracted total bottom production cross section at this energy is \sigma_{b\b^bar}= 3.2 ^{+1.2}_{-1.1}(stat) ^{+1.4}_{-1.3}(syst) micro b.Comment: 432 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Identified charged hadron production in p+p collisions at sqrt(s)=200 and 62.4 GeV

Transverse momentum distributions and yields for $\pi^{\pm}$, $K^{\pm}$, $p$ and $\bar{p}$ in $p+p$ collisions at $\sqrt{s}$=200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). These data provide important baseline spectra for comparisons with identified particle spectra in heavy ion collisions at RHIC. We present the inverse slope parameter $T_{\rm inv}$, mean transverse momentum $$ and yield per unit rapidity $dN/dy$ at each energy, and compare them to other measurements at different $\sqrt{s}$ in $p+p$ and $p+\bar{p}$ collisions. We also present the scaling properties such as $m_T$ scaling, $x_T$ scaling on the $p_T$ spectra between different energies. To discuss the mechanism of the particle production in $p+p$ collisions, the measured spectra are compared to next-to-leading-order or next-to-leading-logarithmic perturbative quantum chromodynamics calculations.Comment: 431 authors from 62 institutions, 32 pages, 23 figures, and 18 tables. Submitted to Physical Review C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm