Measurement of the analyzing power in pp elastic scattering in the peak CNI region at RHIC

We report the first measurements of the A_N absolute value and shape in the -t range from 0.0015 to 0.010GeV/c^2 with a precision better than 0.005 for each A_N data point using a polarized atomic hydrogen gas jet target and the 100 GeV RHIC proton beam.Comment: 4 pages, 5 figure

Precise measurement of positronium hyperfine splitting using the Zeeman effect

Positronium is an ideal system for the research of the quantum electrodynamics (QED) in bound state. The hyperfine splitting (HFS) of positronium, $\Delta_{\mathrm{HFS}}$, gives a good test of the bound state calculations and probes new physics beyond the Standard Model. A new method of QED calculations has revealed the discrepancy by 15\,ppm (3.9$\sigma$) of $\Delta_{\mathrm{HFS}}$ between the QED prediction and the experimental average. There would be possibility of new physics or common systematic uncertainties in the previous all experiments. We describe a new experiment to reduce possible systematic uncertainties and will provide an independent check of the discrepancy. We are now taking data and the current result of $\Delta_{\mathrm{HFS}} = 203.395\,1 \pm 0.002\,4 (\mathrm{stat.}, 12\,\mathrm{ppm}) \pm 0.001\,9 (\mathrm{sys.}, 9.5\,\mathrm{ppm})\,\mathrm{GHz}$ has been obtained so far. A measurement with a precision of $O$(ppm) is expected within a year.Comment: 8 pages, 8 figures, 2 tables, proceeding of LEAP2011, accepted by Hyperfine Interaction

First test of O(α2)O(\alpha ^{2}) correction of the orthopositronium decay rate

Positronium is an ideal system for the research of the bound state QED. New precise measurement of orthopositronium decay rate has been performed with an accuracy of 150 ppm. This result is consistent with the last three results and also the 2nd order correction. The result combined with the last three is 7.0401$\pm0.0007\mu \mathrm{sec}^{-1}$ (100 ppm), which is consistent with the 2nd order correction and differs from the 1st order calculation by 2.6$\sigma$ It is the first test to validate the 2nd order correction.Comment: will be submitted to Phys. Lett.

Immunological profile in a family with nephrogenic diabetes insipidus with a novel 11 kb deletion in AVPR2 and ARHGAP4 genes

<p>Abstract</p> <p>Background</p> <p>Congenital nephrogenic diabetes insipidus (NDI) is characterised by an inability to concentrate urine despite normal or elevated plasma levels of the antidiuretic hormone arginine vasopressin. We report a Japanese extended family with NDI caused by an 11.2-kb deletion that includes the entire <it>AVPR2 </it>locus and approximately half of the <it>Rho GTPase-activating protein 4 </it>(<it>ARHGAP4</it>) locus. ARHGAP4 belongs to the RhoGAP family, Rho GTPases are critical regulators of many cellular activities, such as motility and proliferation which enhances intrinsic GTPase activity.</p> <p>ARHGAP4 is expressed at high levels in hematopoietic cells, and it has been reported that an NDI patient lacking <it>AVPR2 </it>and all of <it>ARHGAP4 </it>showed immunodeficiency characterised by a marked reduction in the number of circulating CD3+ cells and almost complete absence of CD8+ cells.</p> <p>Methods</p> <p>PCR and sequencing were performed to identify the deleted region in the Japanese NDI patients. Immunological profiles of the NDI patients were analysed by flow cytometry. We also investigated the gene expression profiles of peripheral blood mononuclear cells (PBMC) from NDI patients and healthy controls in microarray technique.</p> <p>Results</p> <p>We evaluated subjects (one child and two adults) with 11.2-kb deletion that includes the entire <it>AVPR2 </it>locus and approximately half of the <it>ARHGAP4</it>. Hematologic tests showed a reduction of CD4+ cells in one adult patient, a reduction in CD8+ cells in the paediatric patient, and a slight reduction in the serum IgG levels in the adult patients, but none of them showed susceptibility to infection. Gene expression profiling of PBMC lacking <it>ARHGAP4 </it>revealed that expression of RhoGAP family genes was not influenced greatly by the lack of <it>ARHGAP4</it>.</p> <p>Conclusion</p> <p>These results suggest that loss of <it>ARHGAP4 </it>expression is not compensated for by other family members. ARHGAP4 may play some role in lymphocyte differentiation but partial loss of <it>ARHGAP4 </it>does not result in clinical immunodeficiency.</p

Deuteron and antideuteron production in Au+Au collisions at sqrt(s_NN)=200 GeV

The production of deuterons and antideuterons in the transverse momentum range 1.1 < p_T < 4.3 GeV/c at mid-rapidity in Au + Au collisions at sqrt(s_NN)=200 GeV has been studied by the PHENIX experiment at RHIC. A coalescence analysis comparing the deuteron and antideuteron spectra with those of protons and antiprotons, has been performed. The coalescence probability is equal for both deuterons and antideuterons and increases as a function of p_T, which is consistent with an expanding collision zone. Comparing (anti)proton yields p_bar/p = 0.73 +/- 0.01, with (anti)deuteron yields: d_bar/d = 0.47 +/- 0.03, we estimate that n_bar/n = 0.64 +/- 0.04.Comment: 326 authors, 6 pages text, 5 figures, 1 Table. Submitted to PRL. 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

Mid-Rapidity Direct-Photon Production in p+p Collisions at sqrt(s) = 200 GeV

A measurement of direct photons in p+p collisions at sqrt(s)=200 GeV is presented. A photon excess above background from pi^0 --> gamma+gamma, eta --> gamma+gamma, and other decays is observed in the transverse momentum range 5.5 < p_T < 7 GeV/c. The result is compared to a next-to-leading-order perturbative QCD calculation. Within errors, good agreement is found between the QCD calculation and the measured result.Comment: 330 authors, 7 pages text, RevTeX, 2 figures, 2 tables. Submitted to Physical Review D. 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

Suppressed pi^0 Production at Large Transverse Momentum in Central Au+Au Collisions at sqrt(s_NN) = 200 GeV

Transverse momentum spectra of neutral pions in the range 1 < p_T < 10 GeV/c have been measured at mid-rapidity by the PHENIX experiment at RHIC in Au+Au collisions at sqrt(s_NN) = 200 GeV. The pi^0 multiplicity in central reactions is significantly below the yields measured at the same sqrt(s_NN) in peripheral Au+Au and p+p reactions scaled by the number of nucleon-nucleon collisions. For the most central bin, the suppression factor is ~2.5 at p_T = 2 GeV/c and increases to ~4-5 at p_T ~= 4 GeV/c. At larger p_T, the suppression remains constant within errors. The deficit is already apparent in semi-peripheral reactions and increases smoothly with centrality.Comment: 326 authors, 6 pages text, RevTeX, 3 figures, 2 tables. Submitted to PRL. 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

Scaling properties of proton and anti-proton production in sqrt(s_NN) = 200 GeV Au + Au collisions

We report on the yield of protons and anti-protons, as a function of centrality and transverse momentum, in Au+Au collisions at sqrt(s_NN) = 200 GeV measured at mid-rapidity by the PHENIX experiment at RHIC. In central collisions at intermediate transverse momenta (1.5 < p_T < 4.5 GeV/c) a significant fraction of all produced particles are protons and anti-protons. They show a centrality-scaling behavior different from that of pions. The p-bar/pion and p/pion ratios are enhanced compared to peripheral Au+Au, p+p, and electron+positron collisions. This enhancement is limited to p_T < 5 GeV/c as deduced from the ratio of charged hadrons to pi^0 measured in the range 1.5 < p_T < 9 GeV/c.Comment: 325 authors, 6 pages text, 4 figures, RevTeX 4. Minor changes to text and figures to meet PRL length restrictions; no changes to figures; resubmitted to PRL. 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