Measurement of Analyzing Power for Proton-Carbon Elastic Scattering in the Coulomb-Nuclear Interference Region with a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>22</mml:mn><mml:mtext>−</mml:mtext><mml:mi mathvariant="normal">G</mml:mi><mml:mi mathvariant="normal">e</mml:mi><mml:mi mathvariant="normal">V</mml:mi><mml:mo>/</mml:mo><mml:mi>c</mml:mi></mml:math>Polarized Proton Beam

Tojo, J.; Alekseev, I.; Bai, Mei; Bassalleck, B.; Bunce, G.; Deshpande, A.; Doskow, J.; Eilerts, S.; Fields, D. E.; Goto, Y.; Huang, H.; Hughes, V. W.; Imai, K.; Ishihara, M.; Kanavets, V.P.; Kurita, K.; Kwiatkowski, K.; Lewis, B.; Lozowski, W.; Makdisi, Y. I.; Meyer, H. O.; Morozov, B. V.; Nakamura, Masanobu; Przewoski, B. von; Rinckel, T.; Roser, T.; Rusek, A.; Saito, N.; Smith, Bradford; Svirida, D. N.; Syphers, M.; Taketani, A.; Thomas, T. L.; Underwood, D. G.; Wolfe, D.; Yamamoto, Kentaro; Zhu, Lei

doi:10.1103/physrevlett.89.052302

Cited by 40 publications

(11 citation statements)

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“…It has already been shown that spin-polarized projectile fragments in peripheral collisions are measurable through the angular distribution of γ or β decays at both GSI and RIKEN [19,20]. In addition, at AGS and RHIC energies, people can already obtain the spin-flip probability and distinguish spin-up and spin-down nucleons in elastic pp or pA collisions by measuring the analyzing power [21]. One thus expects that spin-related experimental observables in intermediate-energy heavy-ion collisions can be measured in the near future, if they are indeed helpful for enriching our knowledge about the poorly known inmedium spin-orbit interaction.…”

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confidence: 99%

Probing in-medium spin–orbit interaction with intermediate-energy heavy-ion collisions

2013

Physics Letters B

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Incorporating for the first time both the spin and isospin degrees of freedom explicitly in transport model simulations of intermediate-energy heavy-ion collisions, we observe that a local spin polarization appears during collision process. Most interestingly, it is found that the nucleon spin up-down differential transverse flow is a sensitive probe of the spin-orbit interaction, providing a novel approach to probe both the density and isospin dependence of the in-medium spin-orbit coupling that is important for understanding the structure of rare isotopes and synthesis of superheavy elements. 24.10.Lx, 13.88.+e The spin-orbit coupling is common to the motion of many objects in nature from quarks, nucleons, and electrons to planets and stars. In nuclear physics, it has been very well known for a long time that the spin-orbit coupling is crucial for understanding the structure of finite nuclei, such as the magic numbers [1,2]. However, many interesting questions regarding the in-medium spin-orbit coupling, especially its density and isospin dependence, remain unresolved although in free space it has been well determined from nucleon-nucleon (NN) scattering data [3]. Indeed, several phenomena observed or predicted in studying properties of nuclear structures have been providing us some useful information about the inmedium spin-orbit interaction. For instance, the kink of the charge radii of lead isotopes can only be explained by introducing a weakly isospin-dependent spin-orbit coupling [4,5]. Moreover, strong experimental evidences of a decreasing spin-orbit coupling strength with increasing neutron excess were reported [6,7]. Furthermore, new experiments are currently being carried out at several laboratories to explore the density and isospin dependence of the spin-orbit coupling by comparing energy splittings of certain orbits in the so-called "bubble" nuclei [8,9] with those in normal nuclei [10]. The knowledge of the in-medium spin-orbit interaction is useful for understanding properties of drip-line nuclei [11], the astrophysical r-process [12], and the location of stability island for superheavy elements [13,14].While effects of the spin-orbit interaction on nuclear structure have been studied extensively, very little is known about its effects in heavy-ion collisions. Within the time-dependent Hartree-Fock (TDHF) calculations the nucleon spin-orbit interaction was found to affect the fusion threshold energy [15] and lead to a local spin polarization [16,17]. In non-central relativistic heavyion collisions at 200 GeV/nucleon the partonic spin-orbit coupling was found to lead to a global quark spin polarization [18]. However, to our best knowledge, no study on effects of the spin-orbit interaction in intermediateenergy heavy-ion collisions has been carried out yet. On the other hand, several facilities for spin-polarized beams have been developed for about twenty years. It has already been shown that spin-polarized projectile fragments in peripheral collisions are measurable through the angular distrib...

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confidence: 99%

Probing in-medium spin–orbit interaction with intermediate-energy heavy-ion collisions

2013

Physics Letters B

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“…The Thick curve corresponds to r 5 = 0. Right panel: r 5 correspond to the results of the E950 experiment at BNL [6] as given by (9). Thin curves show the corridor of uncertainty.…”

Section: Cni Revisitedmentioning

confidence: 99%

“…A first time precise measurement of A pA N (t) performed by the E950 collaboration for proton-carbon elastic scattering with 22 GeV polarized beam at AGS [6]. The authors fitted the data with expressions (7)-(8) and found Im r 5 = −0.161 ± 0.226; Re r 5 = 0.088 ± 0.058 .…”

Section: Cni With Nuclear Targets: the E950 Experimentsmentioning

confidence: 99%

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Small Angle Scattering of Polarized Protons

Kopeliovich¹

2003

AIP Conference Proceedings

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Experiment E950 at AGS, BNL has provided data with high statistics for the left-right asymmetry of proton-carbon elastic scattering in the Coulomb-nuclear interference region of momentum transfer. It allows to access information about spin properties of the Pomeron and has practical implications for polarimetry at high energies. Relying on Regge factorization the results for the parameter r_5, ratio of spin-flip to non-flip amplitudes, is compared with the same parameter measured earlier in pion-proton elastic and charge exchange scattering. While data for Im r_5 agree (within large systematic errors), there might be a problem for Re r_5. The \pi N data indicate at a rather small contribution of the f-Reggeon to the spin-flip part of the iso-scalar amplitude which is dominated by the Pomeron. This conclusion is supported by direct analysis of data for elastic and charge exchange pp and pn scattering which also indicate at a vanishing real part of the hadronic spin-flip amplitude at energies 20 GeV and higher. This is a good news for polarimetry, since the E950 results enhanced by forthcoming new measurements at AGS can be safely used for polarimetry at RHIC at higher energies.Comment: 11 pages. Prenary talk at 15th International Spin Physics Symposium "SPIN 2002", Brookhaven National Laborator

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“…Due to the time-reversal invariance, this single-spin correlation in (3) is the same for either initial or final neutron polarization, and the spin correlation averages to zero after the integration over the final neutron's azimuthal angle ϕ . For higher energies at the LHC and RHIC hadron colliders, a similar effect of the spin Coulomb-nuclear interference [19,20] provided a method to measure proton beam polarization at multi-GeV energies [21], presently known as "CNI Polarimetry". Now we proceed to the twisted neutrons and use an approach developed in Ref.…”

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Schwinger scattering of twisted neutrons by nuclei

2019

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Thanks to J. Schwinger, the process of elastic scattering of neutrons by nuclei is known to depend on the interference between a nuclear amplitude and an electromagnetic one for small scattering angles, resulting in spin asymmetries of a cross section or in polarization of the scattered neutrons. While this interference depends on the neutron's transverse polarization and on an imaginary part of the nuclear amplitude, this conclusion holds only for the incident plane-wave neutrons with a definite momentum. Here we show that this scattering is altered when the twisted neutrons, recently obtained experimentally, are used instead -that is, neutrons with an orbital angular momentum. For bulk targets, the angular distributions of the scattered neutrons get modified, while scattering of a superposition of states with the different angular momenta also reveals dependence on the longitudinal polarization. For well-localized targets, the observables develop a dependence on the neutron's helicity and on a real part of the nuclear amplitude, providing full access to its phase already in the Born approximation. We argue that the corresponding spin asymmetries are measurable at existing neutron facilities. Thus, scattering of the twisted neutrons by nuclei can provide means for quantum tomography of the neutron states and become a useful tool for hadronic studies, low-energy nuclear physics, tests of fundamental symmetries, and neutron optics.Introduction. -In 1948 J. Schwinger predicted that in a process of elastic scattering of the non-relativistic neutrons by a nucleus with a charge Ze the final neutrons become spin-polarized, thanks to the spin-orbit coupling [1]. Nowadays such a scattering is well studied, both theoretically [2] and experimentally [3], and the polarized cold and thermal neutrons are needed for a number of standard model test measurements (see, e.g., [4]).

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Measurement of Analyzing Power for Proton-Carbon Elastic Scattering in the Coulomb-Nuclear Interference Region with a22−GeV/cPolarized Proton Beam

Cited by 40 publications

References 15 publications

Probing in-medium spin–orbit interaction with intermediate-energy heavy-ion collisions

Probing in-medium spin–orbit interaction with intermediate-energy heavy-ion collisions

Small Angle Scattering of Polarized Protons

Schwinger scattering of twisted neutrons by nuclei

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