B. v. Przewoski

Publications (20)2.26 Total impact

• Article: Analyzing powers and spin correlation coefficients for p+ d elastic scattering at 135 and 200 MeV

  B. v. Przewoski, H. O. Meyer, J. T. Balewski, W. W. Daehnick, J. Doskow, W. Haeberli, R. Ibald, B. Lorentz, R. E. Pollock, P. V. Pancella, F. Rathmann, T. Rinckel, Swapan K. Saha, B. Schwartz, P. Thörngren-Engblom, A. Wellinghausen, T. J. Whitaker, T. Wise
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  ABSTRACT: The proton and deuteron analyzing powers and ten of the possible 12 spin correlation coefficients have been measured for p+d elastic scattering at proton bombarding energies of 135 and 200 MeV. The results are compared with Faddeev calculations using two different NN potentials. The qualitative features of the extensive data set on the spin dependence in p+d elastic scattering over a wide range of angles presented here are remarkably well explained by two-nucleon force predictions without inclusion of a three-nucleon force. The remaining discrepancies are, in general, not alleviated when theoretical three-nucleon forces are included in the calculations.
  Phys. Rev. C. 12/2006; 74(6).
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  Available from: H.O. Meyer

  Article: Analyzing Powers and Spin Correlation Coefficients for p+d Elastic Scattering at 135 and 200 MeV

  B. v. Przewoski, H.O. Meyer, J. T. Balewski, W.W. Daehnick, J. Doskow, W. Haeberli, R. Ibald, B. Lorentz, R.E. Pollock, P.V. Pancella, F. Rathmann, T. Rinckel, Swapan K. Saha, B. Schwartz, P. Thoerngren Engblom, A. Wellinghausen, T. J. Whitaker, T. Wise, H. Witala
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  ABSTRACT: The proton and deuteron analyzing powers and 10 of the possible 12 spin correlation coefficients have been measured for p+d elastic scattering at proton bombarding energies of 135 and 200 MeV. The results are compared with Faddeev calculations using two different NN potentials. The qualitative features of the extensive data set on the spin dependence in p+d elastic scattering over a wide range of angles presented here are remarkably well explained by two-nucleon force predictions without inclusion of a three-nucleon force. The remaining discrepancies are, in general, not alleviated when theoretical three-nucleon forces are included in the calculations.
  12/2004;
• Article: Vector and tensor polarization lifetimes for a stored deuteron beam.

  B V Przewoski, V A Anferov, H O Meyer, P Schwandt, E J Stephenson, V S Morozov, Z B Etienne, M C Kandes, M A Leonova, D W Sivers, K Yonehara
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  ABSTRACT: The time dependence of the vector and tensor polarization of a 270 MeV stored deuteron beam was measured near a depolarizing resonance, which was induced by an oscillating, longitudinal magnetic field. The distance to the resonance was varied by changing the oscillation frequency. The measured ratio of the polarization lifetimes is tau(vector)/tau(tensor)=1.9+/-0.2. Assuming that the effect of the resonance is to induce transitions between magnetic substates m(I), we find that the transition rate between neighboring states (+1 and 0 or -1 and 0) is four times higher than between the states with m(I)=+1 and -1.
  Physical Review E 11/2003; 68(4 Pt 2):046501. · 2.26 Impact Factor
• Article: Complete Set of Polarization Observables in pp arrow pp π^0 near Threshold

  H. O. Meyer, A. Wellinghausen, J. T. Balewski, J. Doskow, R. E. Pollock, B. V. Przewoski, T. Rinckel, P. Thörngren-Engblom, L. D. Knutson, W. Haeberli, B. Lorentz, F. Rathmann, B. Schwartz, T. Wise, W. W. Daehnick, Swapan K. Saha, P. V. Pancella
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  ABSTRACT: In a kinematically complete experiment we have measured the two analyzing powers and the five spin correlation coefficients of pp arrow pp π^0 as a function of all five parameters of the three-body final state for bombarding energies between 325 and 400 MeV. The experiment was carried out at the Indiana Cooler Storage Ring. Below 400 MeV, a total of 12 complex partial-wave amplitudes are significant. We have developed a formalism for an expansion of the spin observables of a reaction with polarized spin-1/2 collision partners and a three-body final state into a complete set of angular functions. We use this expansion to completely describe the polarization information obtainable in neutral pion production by colliding polarized protons.
  09/2001; -1.
• Article: Analyzing power in CNI-region at AGS (experiment E950)

  I. G. Alekseev, M. Bai, B. Bassalleck, G. Bunce, A. Deshpande, J. Doskow, S. Eilerts, D. E. Fields, Y. Goto, K. Imai, [......], B. Smith, D. N. Svirida, M. Syphers, A. Taketani, T. L. Thomas, J. Tojo, D. Underwood, D. Wolfe, K. Yamamoto, L. Zhu
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  ABSTRACT: Acceleration of polarized protons is one of the exciting features of the new Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Measurements of beam polarization are required both for experiments and the accelerator tuning. Elastic scattering in the Coulomb nuclear interference (CNI) region of polarized proton beams on a carbon target demonstrates asymmetry which can be used to build a polarimeter. The methods proposed for a RHIC CNI polarimeter were tested with the AGS polarized beam in the E950 experiment. A 21.7 GeV/c polarized proton beam was scattered on an extremely thin carbon ribbon target located in the AGS ring. Two symmetrical arms consisting of silicon strip detectors (SSD) and a micro channel plate (MCP) were used to identify recoil carbon. Data obtained demonstrates a good identification of the reaction by the apparatus and a significant analyzing power. A RHIC polarimeter setup with 4 SSDs but without MCPs will be used to commission RHIC with polarized protons and for the first spin physics running in 2001. © 2000 American Institute of Physics.
  AIP Conference Proceedings. 12/2000; 549(1):670-673.
• Article: Spin correlation coefficients in pvec pvec-->pnπ+ from 325 to 400 MeV

  Swapan K. Saha, W. W. Daehnick, R. W. Flammang, J. T. Balewski, H. O. Meyer, R. E. Pollock, B. V. Przewoski, T. Rinckel, P. Thörngren-Engblom, B. Lorentz, F. Rathmann, B. Schwartz, T. Wise, P. V. Pancella
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  ABSTRACT: The spin correlation coefficient combinations S≡Axx+Ayy, D≡Axx-Ayy and the analyzing powers Ay(θ) were measured for pvec pvec-->pnπ+ at beam energies of 325, 350, 375 and 400 MeV. A polarized internal atomic hydrogen target and a stored, polarized proton beam were used. These polarization observables are sensitive to contributions of higher partial waves. A comparison with recent theoretical calculations is provided. .
  05/2000; 512:37-42.
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  Available from: H.O. Meyer

  Article: Measurement of Spin Correlation coefficients in \vec p \vec p --> d pi^+

  B. v. Przewoski, J. T. Balewski, J. Doskow, H.O. Meyer, R.E. Pollock, T. Rinckel, P. Thörngren-Engblom, A. Wellinghausen, W. Haeberli, B. Lorentz, F. Rathmann, B. Schwartz, T. Wise, W.W. Daehnick, Swapan K. Saha, P.V. Pancella
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  ABSTRACT: The spin correlation coefficent combinations A_{xx}+A_{yy} and A_{xx}-A_{yy}, the spin correlation coefficients A_{xz} and A_{zz}, and the analyzing power were measured for \vec p \vec p --> d pi^+ between center-of-mass angles 25 deg \leq \theta \leq 65 deg at beam energies of 350.5, 375.0 and 400.0 MeV. The experiment was carried out with a polarized internal target and a stored, polarized beam. Non-vertical beam polarization needed for the measurement of A_{zz} was obtained by the use of solenoidal spin rotators. Near threshold, only a few partial waves contribute, and pion s- and p-waves dominate with a possible small admixture of d-waves. Certain combinations of the observables reported here are a direct measure of these d-waves. The d-wave contributions are found to be negligible even at 400.0 MeV. Comment: 6 pages, 1 figure
  12/1999;
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  Available from: H.O. Meyer

  Article: Measurement of Partial-Wave Contributions in pp --> pp pi^0

  H.O. Meyer, J. T. Balewski, J. Doskow, R.E. Pollock, B. v. Przewoski, T. Rinckel, P. Thorngren Engblom, A. Wellinghausen, W. Haeberli, B. Lorentz, F. Rathmann, B. Schwartz, T. Wise, W.W. Daehnick, Swapan K. Saha, P.V. Pancella
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  ABSTRACT: We report a measurement of the spin-dependent total cross section ratios delta_sigma_T/sigma_tot and delta_sigma_L/sigma_tot of the pp --> pp pi^0 reaction between 325 MeV and 400 MeV. The experiment was carried out with a polarized internal target in a storage ring. Non-vertical beam polarization was obtained by the use of solenoidal spin rotators. Near threshold, the knowledge of both spin-dependent total cross sections is sufficient to deduce the strength of certain participating partial waves, free of any model. Comment: 6 pages, 4 figures
  07/1999;
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  Available from: H.O. Meyer

  Article: Spin Correlation Coefficients in pp-->pnpi+ from 325 to 400 MeV

  Swapan K. Saha, W.W. Daehnick, R. W. Flammang, J. T. Balewski, H.O. Meyer, R.E. Pollock, B. v. Przewoski, T. Rinckel, P. Thorngren Engblom, B. Lorentz, F. Rathmann, B. Schwartz, T. Wise, P.V. Pancella
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  ABSTRACT: The spin correlation coefficient combinations Axx + Ayy, Axx - Ayy and the analyzing powers Ay(theta) were measured for pp-->pnpi+ at beam energies of 325, 350, 375 and 400 MeV. A polarized internal atomic hydrogen target and a stored, polarized proton beam were used. These polarization observables are sensitive to contributions of higher partial waves. A comparison with recent theoretical calculations is provided. Comment: 8 Pages, 1 Table, 5 Figures. Accepted for publication in Phys. Lett. B
  07/1999;
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  Available from: H.O. Meyer

  Conference Proceeding: A p-carbon CNI polarimeter for RHIC

  H. Huang, M. Bai, G. Bunce, Y. Makdisi, T. Roser, K. Imai, M. Nakamura, J. Tojo, K. Yamamoto, L. Zhu, [......], H.O. Meyer, B.V. Przewoski, T. Rinckel, S.B. Nurushev, M.N. Strikhanov, M.F. Runtzo, I.G. Alekseev, D.N. Svirida, A. Deshpande, V. Hughes
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  ABSTRACT: The RHIC spin program requires excellent polarimetry so that the knowledge of the beam polarization does not limit the errors on the experimental measurements. However, polarimetry of proton beams with energies higher than about 30 GeV poses a difficult challenge. For polarization monitoring during operation, a fast and reliable polarimeter is required that produces a polarization measurement with a 10% relative error within a few minutes. The p-carbon elastic scattering in the Coulomb-nuclear-scattering (CNI) region has a calculable and large analyzing power, but detecting the recoil carbon needs a sophisticated detector system and a very thin target. An experiment has been planned in the AGS. This paper describes the experimental setup in the AGS
  Particle Accelerator Conference, 1999. Proceedings of the 1999; 02/1999
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  Available from: H.O. Meyer

  Article: Polarization Observables of pp -> pp pi0 Near Threshold

  P. Thorngren Engblom, H.O. Meyer, J. T. Balewski, J. Doskow, R.E. Pollock, B. v. Przewoski, T. Rinckel, F. Sperisen, W.W. Daehnick, Swapan K. Saha, W. Haeberli, B. Lorentz, F. Rathmann, B. Schwartz, T. Wise, P.V. Pancella
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  ABSTRACT: With the aim to study spin dependence of pion production near threshold, an internal target facility and a forward detector have been installed in the Cooler synchrotron ring at IUCF. The detector system comprises scintillators and wire chambers. The target consists of a thin-walled open-ended storage cell into which polarized atomic hydrogen is injected. Using a stored and cooled, polarized proton beam, polarization observables of the reaction pp -> pp pi0 have been studied at energies between 21 and 55 MeV above the pion production threshold in the center of mass system. We report here measurements of the spin correlation parameters Axx and Ayy, and the analyzing power Ay, integrated over the pion polar angle.
  11/1998;
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  Available from: H.O. Meyer

  Article: Dependence of pp->pp pi0 near Threshold on the Spin of the Colliding Nucleons

  H.O. Meyer, J. T. Balewski, M. Dzemidzic, J. Doskow, R.E. Pollock, B. v. Przewoski, T. Rinckel, F. Sperisen, P. Thörngren-Engblom, M. Wolanski, W. Haeberli, B. Lorentz, F. Rathmann, B. Schwartz, T. Wise, W.W. Daehnick, R. W. Flammang, Swapan K. Saha, D. J. Tedeschi, P.V. Pancella
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  ABSTRACT: A polarized internal atomic hydrogen target and a stored, polarized beam are used to measure the spin-dependent total cross section Delta_sigma_T/sigma_tot, as well as the polar integrals of the spin correlation coefficient combination A_xx-A_yy, and the analyzing power A_y for pp-> pp pi0 at four bombarding energies between 325 and 400 MeV. This experiment is made possible by the use of a cooled beam in a storage ring. The polarization observables are used to study the contribution from individual partial waves. Comment: 6 pages, 1 table, 4 figures, corrected equations 2 and 3
  07/1998;
• Article: Cross sections and analyzing powers of {ital p}({ital {rvec p}},{pi}{sup +}){ital d} very near threshold

  P. Heimberg, R.E. Segel, F. Chen, K. Ackerstaff, R.D. Bent, J. Blomgren, H.O. Meyer, H. Nann, B.v. Przewoski, T. Rinckel, A. Zhuralev, M.A. Pickar, G. Hardie, P. Pancella, E. Jacobsen, J.D. Brown
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  ABSTRACT: Analyzing powers and total cross sections for the p({rvec p},{pi}{sup +})d reaction near threshold have been measured at the Indiana University Cyclotron Facility Cooler. The analyzing power follows a sin {theta}{sub cm} distribution. These preliminary results are consistent with the calculated factor of two enhancement of the s-wave cross section from heavy meson exchange currents. (AIP)
  AIP Conference Proceedings 07/1995; 339(1).
• Article: Polarization measurements of a storage cell target

  M. A. Ross, A. D. Roberts, T. Wise, W. Haeberli, W. A. DeZarn, J. Doskow, H. O. Meyer, R. E. Pollock, B. v. Przewoski, T. Rinckel, F. Sperisen, P. V. Pancella
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  ABSTRACT: A storage cell has been constructed for use as an internal target at the IUCF electron‐cooled storage ring (Cooler). We report on nuclear polarization measurements of hydrogen, produced by an atomic beam source (ABS), in this storage cell. The results indicate a target polarization in excess of 0.70 for atoms in a single spin state.
  AIP Conference Proceedings. 12/1993; 293(1):14-17.
• Article: Calibration of the polarization of a beam of arbitrary energy in a storage ring

  R. E. Pollock, W. A. Dezarn, M. Dzemidzic, J. Doskow, J. G. Hardie, H. O. Meyer, B. v. Przewoski, T. Rinckel, F. Sperisen, W. Haeberli, B. Lorentz, F. Rathmann, T. Wise, P. V. Pancella
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  ABSTRACT: With a storage ring synchrotron, two additional methods have become possible to establish polarization standards at arbitrary energies, making use of the ease with which the energy of the stored beam can be changed. Both methods yield the analyzing power of a reaction at one energy in relation to the known analyzing power at a different energy. One method involves ramping of the energy of a polarized beam up and down; the other requires a polarized target. The two methods have been demonstrated in an experiment with the Indiana Cooler, and their relative consistency has been established.
  Phys. Rev. E. 55(6).
• Article: Proton-proton analyzing power and spin correlation measurements between 250 and 450 MeV at 7°<~ θ_ {cm}<~ 90° with an internal target in a storage ring

  B. v. Przewoski, F. Rathmann, W. A. Dezarn, J. Doskow, M. Dzemidzic, W. Haeberli, J. G. Hardie, B. Lorentz, H. O. Meyer, P. V. Pancella, R. E. Pollock, T. Rinckel, F. Sperisen, T. Wise
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  ABSTRACT: We have measured the pp spin correlation coefficients Axx, Ayy, Axz and the analyzing power Ay at 250.0, 280.0, 294.4, 310.0, 350.0, 399.1, and 448.9 MeV over the laboratory angular range 3.5°–43.5° (θc.m.=7°–90°). The statistical accuracy is approximately ±0.006 for Ay and ±0.02 for Amn per 1° angle bin, while the corresponding scale factor uncertainties are 1.3 and 2.5 %, respectively. The experiment makes use of a polarized hydrogen gas target internal to a proton storage ring (IUCF Cooler) and a circulating beam of polarized protons. The method of calibration relative to pp spin correlation coefficients and analyzing power at 197.4 MeV, the injection energy, involves up and down ramping of the energy of the polarized beam. The data are compared to recent pp partial waves analyses and NN potential models, emphasizing in particular the energy dependence in the region of the pion production threshold.
  Phys. Rev. C. 58(4).
• Article: Observation of a large longitudinal analyzing power in a nuclear reaction

  H.O. Meyer, L.D. Knutson, J.T. Balewski, W.W. Daehnick, J. Doskow, W. Haeberli, B. Lorentz, R.E. Pollock, P.V. Pancella, B. v. Przewoski, F. Rathmann, T. Rinckel, Swapan K. Saha, B. Schwartz, P. Thörngren-Engblom, A. Wellinghausen, T. Wise
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  ABSTRACT: We have measured the longitudinal analyzing power Az of the pp→ppπ0 reaction at 375 MeV bombarding energy. We find that for certain angle combinations of the outgoing particles the observed Az is as large as 0.3, demonstrating that sizeable longitudinal analyzing powers in reactions with multi-particle final states are possible. This result has implications for pp parity violation experiments above the pion threshold. The observed Az is dominated by the interference between s and p wave pions in conjunction with nucleon-nucleon P waves in the final state.
  Physics Letters B.
• Article: Beam loss rates with an internal gas target in an electron-cooled storage ring Implications for luminosity optimization

  R.E. Pollock, V. Derenchuk, X. Pei, T. Sloan, F. Sperisen, H.-O. Meyer, B. v. Przewoski, T. Rinckel, P. Pancella, M.A. Ross, W.K. Pitts
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  ABSTRACT: Measurements have been made in the Cooler ring at the Indiana University Cyclotron Facility (IUCF) of the mean lifetime of stored and electron-cooled proton beams in the presence of various target gas species at two ring locations differing in dispersion. A broad range of beam energy Tb, target atomic number Zt and thickness xt was employed. The loss (removal) cross sectionσL per target atom, extracted from the lifetime measurement, exhibits a minimum for small xt which is found to scale with . This behavior is expected because forward Coulomb scattering from target nuclei should be the dominant loss mechanism under the conditions of measurement. A marked increase in σL for larger xt is attributed to emittance growth arising from multiple scattering in competition with the transverse cooling rate. Lattice dispersion at the target increases the contribution to beam heating by electrons in the target atoms and introduces an additional loss mechanism. From the measured σL and beam lifetime, a time cycle may be selected which gives the optimum time-averaged luminosity for a given experiment. Scaling of σL allows prediction of the optimum luminosity over the full operating regime of the cooling ring.
  Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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  Article: Elastic pd scattering with 200–300 MeV protons

  H Rohdjeß, W. Scobel, H.O. Meyer, P.V. Pancella, S F Pate, M.A. Pickar, R.E. Pollock, B. v. Przewoski, T. Rinckel, F. Sperisen, H Witała, J. Golak, D Hüber, H Kamada, W. Glöckle
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  ABSTRACT: We have measured the pd elastic scattering with an electron-cooled beam of a proton storage ring and an internal jet target operated with HD gas. The accurately known H/D ratio is used to transfer the precision of existing pp scattering data to the pd cross sections. Measurements were performed for proton energies between 200 and 300 MeV in the angular range 11°<~Θc.m.<~  29°. The results are compared to nonrelativistic Faddeev calculations with different nucleon-nucleon interactions and total angular momenta j<~5 in the NN subsystem. The impact of a genuine 3N force is investigated. The discrepancies between data and calculations increase with projectile energy.
• Article: Polarization lifetime near an intrinsic depolarizing resonance

  H. O. Meyer, B. Lorentz, M. Dzemidzic, J. Doskow, W. Haeberli, P. V. Pancella, R. E. Pollock, B. v. Przewoski, F. Rathmann, T. Rinckel, F. Sperisen, T. Wise
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  ABSTRACT: We have measured the time dependence of the polarization of a stored proton beam near an intrinsic depolarizing resonance. The distance to the resonance was varied by changing the vertical tune of the storage ring. The measurements are consistent with exponential decay and with a simple model for the change of the lifetime as the resonance is approached. It was originally expected that the presence of an internal target stimulates depolarization; however, we found no evidence for such an effect.
  Phys. Rev. E. 56(3).