study by spin tracking of a storage ring for deuteron electric dipole moment (dedm)
DESCRIPTION
Study by Spin Tracking of A Storage Ring for Deuteron Electric Dipole Moment (dEDM). Fanglei Lin. The 18th International Symposium on Spin Physics U. of Virginia, Oct. 6-11 2008. Acknowledgements. dEDM experiment particle tracking group: - PowerPoint PPT PresentationTRANSCRIPT
Study by Spin Tracking of A Storage Ring for Deuteron Electric Dipole Moment (dEDM)
Fanglei Lin
The 18th International Symposium on Spin Physics
U. of Virginia, Oct. 6-11 2008
The 18th International Symposium on Spin Physics F.Lin
Acknowledgements
dEDM experiment particle tracking group:
BNL Physics Dept. : Yannis K. Semerzidis (Leader) Bill Morse, Vasily Dzhordzhadze BNL CAD : Alfredo U. Luccio BNL NSLS II : Nikolay Malitsky Cornell University : Yuri F.Orlov Indiana University : Edward J. Stephenson KVI : Gerco Onderwater
The 18th International Symposium on Spin Physics F.Lin
Motivation of Deuteron EDM
High sensitivity to CP-violation, complementary and better than nEDM
Physics beyond the SM (esp. SUSY) expect CP-violation within reach
Great sensitivity to T-odd Nuclear Forces If observed it will provide a new, large source of
CP-violation that could explain the Baryon Asymmetry of our Universe (BAU)
Marciano 9/2006
The 18th International Symposium on Spin Physics F.Lin
Concept of dEDM Experiment
Method: Searching for the EDM in a storage ring using the longitudinally polarized deuteron beam.
ESdBSdt
dS
Spin precession due to electric dipole momentSpin precession due to magnetic moment
])1
1([
2 c
EaBa
m
ea
][ B
c
Ecdedm
0 EB
B
E
(vertical) (radial)
Rotating spin about the vertical direction Increasing vertical component of spin
)sin()( 0
tPtP edm
V22aedm The change in the vertical polarization
due to EDM signal :
VPP Prolong polarization life time
a edm Choose proper radial and vertical B
E
The 18th International Symposium on Spin Physics F.Lin
Deuteron Storage Ring
can be controlled by tuning
and
BE section :
• is vertical magnetic field
• is radial electric field
VB
RE
]))(([ 2RVa E
p
mcaaB
m
e
Spin precess frequency :
VB RE
a
Frozen Spin
The 18th International Symposium on Spin Physics F.Lin
Deuteron Storage Ring
Deuteron Momentum (Gev/c)
1.0
Rigidity (Tm) 3.336
Length of orbit (m)
85.4
Magnetic field (T)
0.482
Electric field (MV/m)
12.0
BE section length (m)
3.3
BE section radius (m)
8.406
Maximum of beta function (x;y) (m)
12 ; 15
Length of straight section (m)
9.44
The 18th International Symposium on Spin Physics F.Lin
Correction of Spin Frequency Perturbation
222)( yaxap
pa yxp
a
a
Spin frequency perturbation comes from the second order effects of betatron and synchrotron violation:
)( 22'' yxBB sexty Sextupole produces a quadratic field as
)cos(0
sstp
p
p
p
p
p
p
psDtsx xyxx
)()cos()(
)cos()( yyyy tsy
Conclusion:
The proposed of is possible in principle with the help of sextupoles
s
xD Three sets of sextupoles, locating at large dispersion , large horizontal beta function and large vertical beta function , and are needed for the correction of spin frequency perturbation respectively
x
y
The 18th International Symposium on Spin Physics F.Lin
Simulation tools : UAL (courtesy of N. Malitsky ) + SPINK (courtesy of A.U. Luccio ) Multiparticles with Gaussian distribution All Initial spin vectors points to the longitudinal direction Distribution categories:
Horizontal distribution with Vertical distribution with Momentum spread
Definition of Sx, Sy, Sz, S <Sx> : radial component of polarization <Sy> : vertical component of polarization <Sz> : longitudinal component of polarization S :
1 million turns ~ 1.5 second
Simulation Conditions
222 zyx SSSS
mradmmx 0.3
mradmmy 0.5
310p
p
The 18th International Symposium on Spin Physics F.Lin
The horizontal beta function is maximum at focusing quads. Those sextupoles next to focusing quads. are mainly used to correct the spin frequency perturbation due to the horizontal betatron motion.
Searching for optimum sextupoles (I)
The 18th International Symposium on Spin Physics F.Lin
The vertical beta function is maximum at defocusing quads. Those sextupoles next to defocusing quads. are mainly used to correct the spin frequency perturbation due to the vertical betatron motion.
Searching for optimum sextupoles (II)
The 18th International Symposium on Spin Physics F.Lin
Searching for optimum sextupoles (III)
Two sets of sextupoles are next to focusing and defocusing quads. Both horizontal and vertical motion are included.
The 18th International Symposium on Spin Physics F.Lin
Searching for optimum sextupoles (IV)
Besides two sets of sextupoles next to focusing and defocusing quads, a third set of sectuopole component is introduced in the BE section . Both horizontal and vertical motion are included.
The 18th International Symposium on Spin Physics F.Lin
Searching for optimum sextupoles (V)
Three sets of sextupoles are located next to focusing, defocusing quads and in the BE section . Particles with horizontal, vertical motion and momentum spread are included.
The 18th International Symposium on Spin Physics F.Lin
Summary
Deuteron EDM experiment has the potential to increase the sensitivity to CP violation by several orders of magnitude larger than nEDM
Storage ring provides a clear environment to maintain an intense polarized deuteron beam
Frozen spin method can be implemented by dipoles combining vertical magnetic and radial electric field
Quadratic perturbation in the spin precession frequency can be cancelled with a proper arrangement of sextupoles
Preliminary particle trackings in simulation have already shown a prolonged polarization lifetime with the help of sextupoles.
The 18th International Symposium on Spin Physics F.Lin
Thank You !