Partial Wave Analysis of J/ψ→γ(K+K−π+π−)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

BES data on $J/\psi \to \gamma (K^+K^-\pi^+\pi^-)$ are presented. The $K^*\bar K^*$ contribution peaks strongly near threshold. It is fitted with a broad $0^{-+}$ resonance with mass $M = 1800 \pm 100$ MeV, width $\Gamma = 500 \pm 200$ MeV. A broad $2^{++}$ resonance peaking at 2020 MeV is also required with width $\sim 500$ MeV. There is further evidence for a $2^{-+}$ component peaking at 2.55 GeV. The non-$K^*\bar K^*$ contribution is close to phase space; it peaks at 2.6 GeV and is very different from $K^{*}\bar{K^{*}}$.Comment: 15 pages, 6 figures, 1 table, Submitted to PL

Single Spin Asymmetry ANA_N in Polarized Proton-Proton Elastic Scattering at s=200\sqrt{s}=200 GeV

We report a high precision measurement of the transverse single spin asymmetry $A_N$ at the center of mass energy $\sqrt{s}=200$ GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The $A_N$ was measured in the four-momentum transfer squared $t$ range $0.003 \leqslant |t| \leqslant 0.035$ \GeVcSq, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of $A_N$ and its $t$-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this $\sqrt{s}$, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure

Measurement Of Charge Multiplicity Asymmetry Correlations In High-energy Nucleus-nucleus Collisions At Snn =200 Gev

A study is reported of the same- and opposite-sign charge-dependent azimuthal correlations with respect to the event plane in Au+Au collisions at sNN=200 GeV. The charge multiplicity asymmetries between the up/down and left/right hemispheres relative to the event plane are utilized. The contributions from statistical fluctuations and detector effects were subtracted from the (co-)variance of the observed charge multiplicity asymmetries. In the mid- to most-central collisions, the same- (opposite-) sign pairs are preferentially emitted in back-to-back (aligned on the same-side) directions. The charge separation across the event plane, measured by the difference, Δ, between the like- and unlike-sign up/down-left/right correlations, is largest near the event plane. The difference is found to be proportional to the event-by-event final-state particle ellipticity (via the observed second-order harmonic v2obs), where Δ=[1.3±1.4(stat)-1.0+4.0(syst)]×10- 5+[3.2±0.2(stat)-0.3+0.4(syst)]×10-3v2obs for 20-40% Au+Au collisions. The implications for the proposed chiral magnetic effect are discussed. © 2014 American Physical Society.894NRF-2012004024; National Research FoundationArsene, I., (2005) Nucl. Phys. A, 757, p. 1. , (BRAHMS Collaboration),. NUPABL 0375-9474 10.1016/j.nuclphysa.2005.02.130Back, B.B., (2005) Nucl. Phys. A, 757, p. 28. , (PHOBOS Collaboration),. NUPABL 0375-9474 10.1016/j.nuclphysa.2005.03.084Adams, J., (2005) Nucl. Phys. A, 757, p. 102. , (STAR Collaboration),. NUPABL 0375-9474 10.1016/j.nuclphysa.2005.03.085Adcox, K., (2005) Nucl. Phys. A, 757, p. 184. , (PHENIX Collaboration),. NUPABL 0375-9474 10.1016/j.nuclphysa.2005.03.086Lee, T.D., (1973) Phys. Rev. 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Momentum scale calibration of the LHCb spectrometer

For accurate determination of particle masses accurate knowledge of the momentum scale of the detectors is crucial. The procedure used to calibrate the momentum scale of the LHCb spectrometer is described and illustrated using the performance obtained with an integrated luminosity of 1.6 fb-1 collected during 2016 in pp running. The procedure uses large samples of J/ψ → μ + μ - and B+ → J/ψ K + decays and leads to a relative accuracy of 3 × 10-4 on the momentum scale

Helium identification with LHCb

The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using pp collision data at √(s) = 13 TeV recorded by the LHCb experiment in the years 2016 to 2018, corresponding to an integrated luminosity of 5.5 fb-1. A total of around 105 helium and antihelium candidates are identified with negligible background contamination. The helium identification efficiency is estimated to be approximately 50% with a corresponding background rejection rate of up to O(10^12). These results demonstrate the feasibility of a rich programme of measurements of QCD and astrophysics interest involving light nuclei

Curvature-bias corrections using a pseudomass method

Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy √(s)=13 TeV during 2016, 2017 and 2018. The biases are determined using Z→μ + μ - decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10-4 GeV-1 level, improves the Z→μ + μ - mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass

Magnetic properties of rapidly quenched RE-Fe-Al alloys with RE=Nd and Y

Materials Science Forum312539-544MSFO

On the role of the islets of Langerhans in pancreatic cancer

Pancreatic cancer is a devastating disease characterized by a dismal prognosis with most patients dying within six months after diagnosis. Surgery is an option in less than one in five of these patients, and even with tumor resection the majority of patients succumb to the disease. Other effective treatment options are not available. Common features of pancreatic cancer are severe cachexia, marked insulin resistance and diabetes mellitus. Several studies have demonstrated connections between pancreatic cancers and the endocrine pancreas and this has raised questions regarding the role of the islets of Langerhans in pancreatic adenocarcinoma. This manuscript reviews the recent literature in this field and addresses several questions regarding the interaction between the islets of Langerhans and pancreatic cancer. This review considers the histological findings in pancreatic cancer, cell culture and animal experiments, the four islet cell types and the hormones they secrete, as well as the influence of the arachidonic acid pathways on islet cell function and pancreatic cancer. While pancreatic adenocarcinomas are ductal in nature, the cell of origin has not been identified and there is even some evidence that the islets may harbor the precursor cell. Considerable evidence suggests that the diabetes is caused by the tumor, while other studies have identified diabetes as a risk factor. Clearly, the islets are important in many aspects of this disease. However, even though progress has been made, some questions regarding the interaction of pancreatic cancer and the endocrine pancreas remain unanswered