Erratum: Helicity and transversity distributions of the nucleon and ⌳ hyperon from ⌳ fragmentation †Phys. Rev. D 64, 014017 "2001… ‡

We perform a calculation of the Sivers function in a spectator model of the nucleon, with scalar and axial-vector diquarks. We make use of gluon rescattering to produce the nontrivial phases necessary to generate the Sivers function. The inclusion of axial-vector diquarks enables us to obtain a nonzero Sivers function for down quarks. Using the results of our model, we discuss the phenomenology of transvere single spin asymmetries in pi+, pi-, and pi0 production, which are currently analysed by the HERMES and COMPASS collaborations. We find that the inclusion of axial-vector diquarks substantially reduces the asymmetries.Comment: 8 pages, 7 figures, uses RevTex, added calculation of h1^perp, final version accepted for publication in PL

This paper introduces an experimental probe of the sterile neutrino with a novel, high-intensity source of electron antineutrinos from the production and subsequent decay of 8 Li. When paired with an existing ∼1 kton scintillator-based detector, this Eν =6.4 MeV source opens a wide range of possible searches for beyond standard model physics via studies of the inverse beta decay interaction νe + p → e + + n. In particular, the experimental design described here has unprecedented sensitivity toνe disappearance at ∆m 2 ∼ 1 eV 2 and features the ability to distinguish between the existence of zero, one, and two sterile neutrinos.PACS numbers: 14.60.Pq, 14.60.StThe beta decay-at-rest of 8 Li produces an isotropic electron antineutrino flux with an average energy of 6.4 MeV. An underground liquid scintillator based detector can be used to detect these antineutrinos via the inverse beta decay (IBD) processν e + p → e + + n. The antineutrino rate and energy, peaking at 9 MeV, can be fully reconstructed by the detector. Precise energy and vertex reconstruction opens the possibility of searching for antineutrino disappearance due to oscillations, which, in the simplest two-neutrino form, has the probabilitywhere θ is the disappearance mixing angle; ∆m 2 (eV 2 ) is the squared mass splitting; L is the distance (in meters) from the antineutrino source to the detector; and E (MeV) is the antineutrino energy. This probability is maximized in the range of ∆m 2 ∼ E/L. An existing large scintillator-based antineutrino detector with a diameter of O(10 m), when combined with an 8 Li isotope decay-at-rest source, is sensitive to oscillations at ∆m 2 ∼ 1 eV 2 . This is an oscillation region of high interest due to anomalies that have been observed in the data from LSND [1], MiniBooNE [2], short-baseline reactor studies [3], and gallium source calibration runs [4]. These anomalies are often interpreted as being due to sterile neutrinos [5][6][7][8] and have motivated the development of the IsoDAR (Isotope Decay-At-Rest) concept.IsoDAR-style sources have been considered before [9][10][11]. The design presented here, consisting of an ion source, cyclotron, and target, is the first with a sufficiently high antineutrino flux to address the existence of one or more sterile neutrinos. 5 IBD interactions in a five year run. Such events allow a definitive search for antineutrino oscillations with the added ability to distinguish between models with one and two sterile neutrinos. A sample of more than 7200ν e -electron scatters is also accumulated during this time and can be used as a sensitive electroweak probe.The charged particle beam, used for electron antineutrino production, originates with a 60 MeV/amu cyclotron accelerating 5 mA of H + 2 ions. The design of this compact cyclotron [15] is ongoing and is envisaged as the injector for the accelerator system of the DAEδALUS physics program [16,17]. The IsoDAR design calls for about a factor of six increase in intensity compared to compact cyclotrons used in the medical isotope industry. ...

Space charge effects, being one of the most significant collective effects, play an important role in high intensity cyclotrons. However, for cyclotrons with small turn separation, other existing effects are of equal importance. Interactions of radially neighboring bunches are also present, but their combined effects has not yet been investigated in any great detail. In this paper, a new particle in cell based self-consistent numerical simulation model is presented for the first time. The model covers neighboring bunch effects and is implemented in the three-dimensional object-oriented parallel code OPAL-cycl, a flavor of the OPAL framework. We discuss this model together with its implementation and validation. Simulation results are presented from the PSI 590 MeV Ring Cyclotron in the context of the ongoing high intensity upgrade program, which aims to provide a beam power of 1.8 MW (CW) at the target destination.