Acceleration of polarized protons to 22 GeV/<i>c</i>and the measurement of spin-spin effects in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>↑</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>+<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>↑</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>→p+<i

Khiari, F.Z.; Cameron, P.; Court, G.R.; Crabb, D.; Fujisaki, M.; Gialas, I.; Hansen, P. H.; Hejazifar, M. E.; Krisch, A. D.; Lin, A. M. T.; Linn, S.; Peaslee, D. C.; Raymond, R. S.; Raylman, Raymond R.; Roser, T.; Shima, T.; Terwilliger, K. M.; Ahrens, L.; Alessi, J.; Brown, H.; Brown, K.; Courant, E. D.; Danby, G. T.; Giordano, S.; Halama, H. J.; Kponou, A.; Lambiase, R.; Lee, S. Y.; Lee, Y. Y.; Lockey, R.; Makdisi, Y. I.; Montemurro, P.; Nawrocky, R.J.; Ratner, L. G.; Skelly, J.; Sluyters, T.; Soukas, A.; Tepikian, S.; Witkover, R.; Roberts, J.; Phillips, G.C.; Hughes, V. W.; Schüler, P.; Bywater, J.A.; Martin, Richard L.; O’Fallon, J. R.; Bhatia, T. S.; Northcliffe, L. C.; Simonius, M.

doi:10.1103/physrevd.39.45

Cited by 68 publications

(23 citation statements)

References 94 publications

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“…These tests are much less demanding than asymptotic limits, and apply to an expansion of leading power behavior. The tests fail in almost every case experiments exist [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44]. That is convincing evidence that the observed experimental regularities are not explained by the S D model.…”

supporting

confidence: 51%

Uncovering the scaling laws of hard exclusive hadronic processes in a comprehensive endpoint model

2014

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We show that an endpoint-overlap model can explain the scaling laws observed in exclusive hadronic reactions at large momentum transfer. The model assumes one of the valence quarks carries most of the hadron momentum. Hadron form factors and fixed-angle scattering are related directly to the quark wave function, which can be directly extracted from experimental data. A universal linear endpoint behavior explains the proton electromagnetic form factor, proton-proton fixed-angle scattering, and the t-dependence of proton-proton scattering at large s >> t. Endpoint constituent counting rules relate the number of quarks in a hadron to the power-law behavior. All proton reactions surveyed are consistent with three quarks participating. The model is applicable at laboratory energies and does not need assumptions of asymptotically high energy regime. A rich phenomenology of lepton-hadron scattering and hadron-hadron scattering processes is found in remarkably simple relationships between diverse processes. Experimental regularitiesThe experimental study of differential cross sections of hard exclusive hadronic reactions at high energy reveals a remarkable pattern: They are described by power laws [1][2][3]. A model explanation exists [4][5][6][7], yet it is not satisfactory [8] at the energies of experimental measurements. We are driven to find a consistent explanation of experimental regularities by re-examining all the facts from a fresh point of view."Hard" reactions are those which depend on a single large scale Q 2 > GeV 2 , or several large scales with a fixed ratio. It is remarkable that the proton electromagnetic form factor a e-mail: sumeetkd@iitk.ac.in b e-mail: pkjain@iitk.ac.in c e-mail: ralston@ku.edu F 1 (Q 2 ) agrees well with a decreasing power of Q 2 for Q 2 5 GeV 2 [9]. For large momentum transfer, it is remarkable that pp → pp fixed-angle cross section dσ/dt agrees well with a decreasing power of Q 2 ∼ s [10], where √ s is the center of mass energy. There are many other examples.We have re-evaluated the phenomenology of power-law dependence or "scaling laws" for exclusive reactions. Due to history, the most simple and plausible explanation failed to be developed. The model appears in the literature as the Feynman process, also known as the Drell-Yan model, also known as the endpoint-overlap model [11][12][13]. There is much to be learned and much that is new when the model is objectively explored. The endpoint-overlap modelBefore engaging the technical analysis, a brief synopsis of history is appropriate. It is fair to observe that relatively few papers in recent years have supported the short-distance model that dominated attention earlier. How and why did consideration of soft processes in hard scattering take so long to develop? In their evaluation of the endpoint region, Brodsky and Mueller [14] wrote that "its contribution depends sensitively on the hadronic wave functions". The discussion discovered no actual fault in the endpoint contribution. Instead of finding a flaw, the section end...

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supporting

confidence: 51%

Uncovering the scaling laws of hard exclusive hadronic processes in a comprehensive endpoint model

2014

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“…In addition, since the total polarization loss for the 82 horizontal intrinsic resonances is predicted to be only 15-20% for the given emittance, it is not possible to determine the jump times by time-scanning each resonance individually while measuring the final polarization, as done in the fast tune jump for strong vertical intrinsic resonances [2]. The timing has to be based on accurate beam energy measurement.…”

Section: Horizontal Intrinsic Resonancesmentioning

confidence: 99%

“…Traditionally, the intrinsic resonances are overcome by using a vertical betatron tune jump, which effectively makes the resonance-crossing rate large, and the imperfection resonances are overcome with the harmonic corrections of the vertical orbit to reduce the resonance strength. This has been done at ZGS, KEK, AGS, and COSY [1][2][3]. As the beam energy increases, these traditional methods become difficult and time consuming.…”

Section: Introductionmentioning

confidence: 99%

Overcoming horizontal depolarizing resonances with multiple tune jumps

Huang

Ahrens

Bai

et al. 2014

Phys. Rev. ST Accel. Beams

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In a medium energy proton synchrotron, strong enough partial Siberian snakes can be used to avoid both imperfection and vertical intrinsic depolarizing resonances. However, partial snakes tilt the stable spin direction away from vertical, which generates depolarizing resonances associated with horizontal tune. The relatively weak but numerous horizontal intrinsic resonances are the main source of the residual polarization losses. A pair of horizontal tune jump quads have been used in the Brookhaven Alternating Gradient Synchrotron to overcome these weak resonances. The locations of the two quads have to be chosen such that the disturbance to the beam optics is minimum. The emittance growth has to be mitigated for this method to work. In addition, this technique needs very accurate jump timing. Using two partial Siberian snakes, with vertical tune inside the spin tune gap and 80% polarization at the Alternating Gradient Synchrotron injection, polarized proton beam had reached 1.5 × 10 11 proton per bunch with 65% polarization. With the tune jump timing optimized and emittance preserved, more than 70% polarization with 2 × 10 11 protons per bunch has been achieved. The polarization transport efficiency is close to 90%.

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“…They are especially important at high energy. At lower energy one uses harmonic correction for imperfection spin resonances and fast crossing (FC) for intrinsic resonances [14][15][16][17][18]; recently, the AGS used two weak partial snakes [19]. These techniques are less effective than full snakes and often leave some polarization loss at many of the crossed resonances.…”

mentioning

confidence: 99%

Experimental Test of New Technique to Overcome Spin Depolarizing Resonances

Raymond¹,

Chao²,

Krisch³

et al. 2009

AIP Conference Proceedings

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We recently tested a new spin resonance crossing technique, Kondratenko Crossing (KC), by sweeping an rf-solenoid's frequency through an rf-induced spin resonance with both the KC and traditional fast crossing (FC) patterns. Using both rf bunched and unbunched 1:85 GeV=c polarized deuterons stored in COSY, we varied the parameters of both crossing patterns. Compared to FC with the same crossing speed, KC reduced the depolarization by measured factors of 4:7 AE 0:3 and 19 þ12 À5 for unbunched and bunched beams, respectively. This clearly showed the large potential benefit of Kondratenko Crossing over fast crossing.

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Acceleration of polarized protons to 22 GeV/cand the measurement of spin-spin effects inp↑+p↑→p+

Cited by 68 publications

References 94 publications

Uncovering the scaling laws of hard exclusive hadronic processes in a comprehensive endpoint model

Uncovering the scaling laws of hard exclusive hadronic processes in a comprehensive endpoint model

Overcoming horizontal depolarizing resonances with multiple tune jumps

Experimental Test of New Technique to Overcome Spin Depolarizing Resonances

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