Bulletin of the American Physical Society
2006 APS April Meeting
Saturday–Tuesday, April 22–25, 2006; Dallas, TX
Session C14: Physics of Muon and Polarized Beams |
Hide Abstracts |
Sponsoring Units: DPB Chair: Mike Syphers, Fermi National Accelerator Laboratory Room: Hyatt Regency Dallas Cumberland I |
Saturday, April 22, 2006 1:30PM - 1:42PM |
C14.00001: A Muon Collider as a SUSY Higgs Factory David Cline, Gail Hanson In the Minimal Supersymmetric (SUSY) Standard Model (MSSM) there are five Higgs bosons, the lightest of which $h^0$ will most likely be discovered at the Large Hadron Collider (LHC). However, for moderately large $tan\beta $ the heavier Higgs bosons $A^0$ and $H^0$ may have greatly suppressed couplings to gauge bosons. Discovery of these heavier Higgs bosons may not be possible at the LHC or at an $e^+e^-$ linear collider. In a muon collider Higgs bosons are produced through the $s$-channel, and even in the decoupling limit the couplings of the $A^0$ and $H^0$ to $\mu ^+\mu ^-$ are not suppressed. In this case a muon collider will be needed to discover the $A^0$ and $H^0$. In addition, these heavy Higgs bosons can be largely degenerate, and the very small center-of-mass energy spread of a muon collider will be necessary to separate them. A muon collider as a SUSY Higgs factory will be discussed. [Preview Abstract] |
Saturday, April 22, 2006 1:42PM - 1:54PM |
C14.00002: The Muon Ionization Cooling Experiment Terry Hart Muon storage rings have been proposed for use as sources of intense high-energy neutrino beams and as the basis for multi-TeV lepton-antilepton colliding-beam facilities. Optimizing the performance of such facilities is likely to require the phase-space compression (cooling) of the muon beam prior to acceleration and storage. The short muon lifetime makes traditional beam-cooling techniques ineffective. Ionization cooling, a process in which the muon beam is passed through a series of energy absorbers followed by accelerating RF cavities, is thus the technique of choice. The international Muon Ionization Cooling Experiment (MICE) collaboration has been formed to carry out a muon-cooling demonstration experiment, and its proposal to Rutherford Appleton Laboratory has been approved. The MICE cooling channel, its instrumentation, and its implementation at the Rutherford Appleton Laboratory are described together with the predicted performance of the channel and the measurements that will be made. [Preview Abstract] |
Saturday, April 22, 2006 1:54PM - 2:06PM |
C14.00003: Studies of Six-Dimensional Cooling of a Muon Beam Amit Klier, Gail Hanson The reduction of the phase-space volume (emittance), also known as ``beam cooling,'' is an essential ingredient in muon colliders and is also very useful in neutrino factories. In a muon collider, in particular, the six-dimensional emittance must be reduced by about six orders of magnitude. Ionization cooling is used for transverse emittance reduction. In this process, the beam loses energy through ionizations in an absorber and then regains only longitudinal momentum in RF cavities. Cooling the beam longitudinally is achieved through the process of emittance exchange, in which the beam loses energy by passing through wedge-shaped absorbers in a dispersive magnetic field, designed in such a way that fast muons travel through more absorber material than slow ones and thus lose more energy. Six-dimensional cooling is done by combining the two processes. We simulate cooling channels, in which a muon beam is cooled in all six phase space dimensions while rotating several times in a ring or ring-like cooling channel. Some ring designs and cooling simulation results are presented and discussed. [Preview Abstract] |
Saturday, April 22, 2006 2:06PM - 2:18PM |
C14.00004: The MuCool RF Progarm Alan Bross, Derun Li, Al Moretti, Jim Norem, Zubao Qian, Robert Rimmer, Yagmur Torun, Michael Zisman Cooling muon beams in flight requires absorbers to reduce the muon momentum, accelerating fields to replace the lost momentum, and static solenoidal magnetic fields to focus the muon beams. The process is most efficient if both the magnetic fields and accelerating fields are high and the rf frequency is low. In order to study the interactions of a static magnetic field with the operation of high gradient accelerating fields we have conducted tests to determine the operating envelope of accelerating cavities in high magnetic fields. These studies have already produced useful information on dark currents, magnetic fields and breakdown in cavities. In addition to continuing our program at 805 MHz, we are starting to test a 201 MHz cavity and are planning to look at a variety of appropriate geometries and materials. In parallel with these activities, we are pursuing supporting R{\&}D on models and surface structure. [Preview Abstract] |
Saturday, April 22, 2006 2:18PM - 2:30PM |
C14.00005: Exploration of Horizontal Intrinsic Spin Resonances in the AGS Fanglei Lin, S.Y. Lee, Leif A. Ahrens, Mei Bai, Kevin Brown, Ernest D. Courant, Joseph W. Glenn, Haixin Huang, Alfredo Luccio, William W. MacKay, Vadim Ptitsyn, Thomas Roser, Steven Tepikian, Nicholaos Tsoupas, Jeff Wood, Yin Yip, Masahiro Okamura, Junpei Takano Siberian snakes have been employed to overcome spin resonances during polarized proton acceleration. Considering limited space in the AGS, strong partial snakes that rotate the spin by less than $180$ degrees can be used to avoid the spin imperfection and intrinsic resonances in low energy accelerators. However, the tilt of spin away from the vertical direction may become sensitive to horizontal betatron motion which can also cause spin depolarization. These resonances, called horizontal intrinsic spin resonances, have been observed in simulations. Preliminary measurements with beam were also carried out in AGS 2005 polarized proton run. During the AGS 2006 run, we plan to explore the details about the horizontal intrinsics resonances further. This paper describes the experimental methods and the latest results. [Preview Abstract] |
Saturday, April 22, 2006 2:30PM - 2:42PM |
C14.00006: Spin manipulating vector {\&} tensor polarized deuterons stored in COSY V.S. Morozov, A.D. Krisch, M.A. Leonova, R.S. Raymond, D.W. Sivers, V.K. Wong, K. Yonehara, R. Gebel, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, A. Schnase, H. Stockhorst, D. Eversheim, F. Hinterberger, H. Rohdjess, K. Ulbrich We recently studied the spin manipulation of a simultaneously vector and tensor polarized deuteron beam stored at 1.85 GeV/c in the COSY Cooler Synchrotron. Using the EDDA detector, we first calibrated the vector and tensor analyzing powers, which were earlier unmeasured at 1.85 GeV/c; this allowed us to measure the absolute values of both the vector and tensor polarizations. Then we manipulated the deuteron's polarization by sweeping the frequency of a ferrite rf dipole through an rf-induced spin resonance. We first experimentally determined the resonance's frequency and then varied the rf dipole's frequency sweep range $\Delta $f and frequency ramp time $\Delta $t to maximize the spin-flip efficiency. We then obtained a measured vector spin-flip efficiency of 98.5 $\pm $ 0.3{\%} [1]. We also studied, in detail, the behavior of the tensor polarization during spin manipulation; these new data may allow a better understanding of the interesting quantum behavior of spin-1 bosons. This research was supported by the German BMBF Science Ministry. [1] V.S. Morozov et al., Phys. Rev. ST Accel. Beams 8, 061001 (2005). [Preview Abstract] |
Saturday, April 22, 2006 2:42PM - 2:54PM |
C14.00007: Spin manipulating 2.1 GeV/c polarized protons stored in COSY M.A. Leonova, A.D. Krisch, V.S. Morozov, R.S. Raymond, D.W. Sivers, V.K. Wong, R. Gebel, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, A. Schnase, H. Stockhorst, D. Eversheim, F. Hinterberger, K. Ulbrich We studied spin flipping of a 2.1 GeV/c vertically polarized proton beam stored in COSY. We swept the frequency of a strong ferrite rf-dipole, with $\smallint $\textit{Bdl} = 0.46 T$\cdot $mm, through an rf-induced spin resonance to flip the beam's polarization direction. After determining the resonance's frequency, we varied the frequency ramp time $\Delta $t and frequency range $\Delta $f to maximize the spin-flip efficiency. At the rf-dipole's maximum strength and optimum $\Delta $f and $\Delta $t, we used the multiple spin flip technique to measure a spin-flip efficiency of 99.92 $\pm $ 0.04{\%} [1]. Comparison of the theoretically predicted and experimentally measured rf-induced spin resonance strengths showed that experimentally it was about 10 times stronger than predicted. We then studied this discrepancy by varying the beam size and vertical betatron tune while measuring the strength of the rf-induced spin resonance. We observed a hyperbolic dependence on the distance from an intrinsic spin resonance and no significant dependence on the beam size. This research was supported by the German BMBF Ministry. [1] M.A. Leonova et al., Phys. Rev. Lett. 93, 224801 (2004). [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700