121363109
Status of Rare Isotope Science Project in Korea
The Rare Isotope Science Project (RISP) is launched in Korea to build the IF and ISOL facilities. Current status of RISP is introduced.
120231751
Electron beam line design of A4 Compton backscattering polarimeter
The new beam line has been built to measure the polarization of the electron. The transverse position and emittance of the MAMI beam are determined from measurements of the beam size on three wire scanners. The position measurement has been done and the emittance measurement is still progressing.PACS: 29.27.Eg Beam handling; beam transport – 29.27.Fh Beam characteristics
117000662
Laser Compton polarimetry at JLab and MAMI
Abstract.For modern parity violation experiments it is crucial to measure and monitor the electron beam polarization continuously. In the recent years different high-luminosity concepts, for precision Compton backscattering polarimetry, have been developed, to be used at modern CW electron beam accelerator facilities. As Compton backscattering polarimetry is free of intrinsic systematic uncertainties, it can be a superior alternative to other polarimetry techniques such as Møller and Mott scattering. State-of-the-art high-luminosity Compton backscattering designs currently in use and under development at JLab and Mainz are compared to each other. The latest results from the Mainz A4 Compton polarimeter are presented.
119516709
A luminosity monitor for the A4 parity violation experiment at MAMI
A water Cherenkov luminosity monitor system with associated electronics has been developed for the A4 parity violation experiment at MAMI. The detector system measures the luminosity of the hydrogen target hit by the MAMI electron beam and monitors the stability of the liquid hydrogen target. Both are required for the precise study of the count rate asymmetries in the scattering of longitudinally polarized electrons on unpolarized protons. Any helicity correlated fluctuation of the target density leads to false asymmetries. The performance of the luminosity monitor, investigated in about 2000 h with electron beam, and the results of its application in the A4 experiment are presented.
11251914
Measurement of strange quark contributions to the vector form factors of the proton at Q2 = 0.22 (GeV / c)2.
A new measurement of the parity violating asymmetry in elastic electron scattering on hydrogen at backward angles and at a four momentum transfer of Q;{2} = 0.22 (Ge V / c);{2} is reported here. The measured asymmetry is A_{LR} = (-17.23 +/- 0.82_{stat} +/- 0.89_{syst}) x 10;{-6}. The standard model prediction assuming no strangeness is A_{0} = (-15.87 +/- 1.22) x 10;{-6}. In combination with previous results from measurements at forward angles, it is possible to disentangle for the first time the strange form factors at this momentum transfer, G_{E};{s} = 0.050 +/- 0.038 +/- 0.019 and G_{M};{s} = -0.14 +/- 0.11 +/- 0.11.
6220935
Measurement of the neutron radius of 208Pb through parity violation in electron scattering.
We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.
55977139
TRENDS OF PAPERS PUBLISHED FROM 2006 TO 2010 IN JOURNALS NATURE AND SCIENCE
We present an analysis of the papers published in the journals Nature and Science in the years from 2006 to 2010. During this period, 7788 papers in total were published in the two journals. This includes 544 astronomy papers that correspond to 7.0% of the papers in ‘all’ research fields and 18.9% of those in the field of ‘physical sciences’. The sub-fields of research of the astronomy papers are distributed, in a descending order of the number of papers, in Solar System, stellar astronomy, galaxies and the universe, the Milky Way Galaxy, and exoplanets. The observational facilities used for the studies are mainly ground-based telescopes (31.1%), spacecrafts (27.0%), and space telescopes (22.8%), while 16.0% of papers did not use any noticeable facilities and 1.7% used other facilities. Korean scientists have published 86 papers (33 in Nature and 53 in Science), which is 1.10% of all the papers (N = 7788) in the two journals. The share of papers by Korean astronomers among the scientific papers by Koreans is 8.14%, slightly higher than the contribution of astronomy papers (7.0%) in both journals.
118538298
Exclusive heavy quarkonium + γ production from e+e-annihilation into a virtual photon
We compute the cross section for exclusive production of a photon associated with a heavy quarkonium H of charge-conjugation parity C=+1 from e{sup +}e{sup -} annihilation into a virtual photon at the center-of-momentum energy {radical}(s)=10.58 GeV. The nonrelativistic QCD factorization formulas for the differential and total cross sections are obtained at leading order in the strong coupling and in the relative velocity of the heavy quark in the quarkonium rest frame. The predicted cross sections for the S-wave spin-singlet cases are about 80 fb and 50 fb for H={eta}{sub c} and {eta}{sub c}(2S), respectively. Among P-wave spin-triplet charmonia, {chi}{sub c1} has a particularly large cross section of about 14 fb. The cross sections for bottomonium states {eta}{sub b} and {chi}{sub bJ} are about 3 fb. A rough estimate of the background reveals that the signal significances for charmonium processes are sufficiently large enough to be detected with ease with the integrated luminosities available at the present B factories.
118316737
THE ECLIPSING SYSTEM EP ANDROMEDAE AND ITS CIRCUMBINARY COMPANIONS
We present new long-term CCD photometry for EP And acquired during the period 2007-2012. The light curves display total eclipses at primary minima and season-to-season light variability. Our synthesis for all available light curves indicates that the eclipsing pair is a W-type overcontact binary with parameters of q = 2.578, i = 833, ΔT = 27 K, f = 28%, and l 3 = 2%-3%. The asymmetric light curves in 2007 were satisfactorily modeled by a cool spot on either of the eclipsing components from a magnetic dynamo. Including our 95 timing measurements, a total of 414 times of minimum light spanning about 82 yr was used for a period study. A detailed analysis of the eclipse timing diagram revealed that the orbital period of EP And has varied as a combination of an upward-opening parabola and two periodic variations, with cycle lengths of P 3 = 44.6 yr and P 4 = 1.834 yr and semi-amplitudes of K 3 = 0.0100 days and K 4 = 0.0039 days, respectively. The observed period increase at a fractional rate of +1.39 × 10–10 is in excellent agreement with that calculated from the W-D code and can be plausibly explained by some combination of mass transfer from the primary to the secondary star and angular momentum loss due to magnetic braking. The most reasonable explanation for both cycles is a pair of light-travel-time effects driven by the possible existence of a third and fourth component with projected masses of M 3 = 0.25 M ☉ and M 4 = 0.90 M ☉. The more massive companion could be revealed using high-resolution spectroscopic data extending over the course of a few years and could also be a binary itself. It is possible that the circumbinary objects may have played an important role in the formation and evolution of the eclipsing pair, which would cause it to have a short initial orbital period and thus evolve into an overcontact configuration by angular momentum loss.
118567194
The Light and Period Variations of the Eclipsing Binary AA Ursae Majoris
We present new multiband CCD photometry for AA UMa made on eight nights between 2009 January and March; the R light curves are the first ever compiled. Historical light curves, as well as ours, display partial eclipses and inverse O'Connell effects, with Max I fainter than Max II. Among possible spot models, a cool spot on either of the component stars and its variability with time permit good light-curve representations for the system. A total of 194 eclipse timings over 81 yr, including our five timings, were used for ephemeris computations. We found that the orbital period of the system has varied due to a periodic oscillation overlaid on an upward parabolic variation. The continuous period increase at a fractional rate of +1.3 × 10-10 is consistent with that calculated from the Wilson & Devinney code and can be interpreted as a thermal mass transfer from the less massive to the more massive secondary star at a rate of 6.6 × 10-8 M⊙ yr-1. The periodic component is in satisfactory accord with a light-time effect due to an unseen companion with a period of 28.2 yr, a semiamplitude of 0.007 days, and a minimum mass of M3 sin i3 = 0.25 M⊙, but this period variation could also arise from magnetic activity.
117590086
CHARMONIUM POLARIZATION AT THE TEVATRON
The current issues on the polarization of prompt J/ψ at the Tevatron is discussed. The prediction based on the nonrelativistic QCD factorization approach agrees with measurements from the CDF collaboration at intermediate values of pT, but disagrees at the large values of pT measured.