The spin precession frequency of muons stored in the (g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for a ...nonzero delta omega a(=omega a mu+ - omega a mu-) and a sidereal variation of omega a mu+/-). No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ = -(1.0+/-1.1) x 10(-23) GeV; (m mu dZ0 + HXY)=(1.8+/-6.0) x 10(-23) GeV; and the 95% confidence level limits b perpendicular mu+ <1.4 x 10(-24) GeV and b perpendicular mu- <2.6 x 10(-24) GeV.
A higher precision measurement of the anomalous g value, a(mu)=(g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron, based on data collected in the year ...2000. The result a(mu(+))=11 659 204(7)(5)x10(-10) (0.7 ppm) is in good agreement with previous measurements and has an error about one-half that of the combined previous data. The present world average experimental value is a(mu)(expt)=11 659 203(8)x10(-10) (0.7 ppm).
A precise measurement of the anomalous g value, a(mu) = (g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron. The result a(mu+) = 11 659 202(14) (6) x ...10(-10) (1.3 ppm) is in good agreement with previous measurements and has an error one third that of the combined previous data. The current theoretical value from the standard model is a(mu)(SM) = 11 659 159.6(6.7) x 10(-10) (0.57 ppm) and a(mu)(exp) - a(mu)(SM) = 43(16) x 10(-10) in which a(mu)(exp) is the world average experimental value.
The muon (g 2) experiment E821 is currently in progress at Brookhaven National Laboratory. Four data-taking runs for positive muons and one run for negative muons were successfully accomplished in ...19972000 and 2001, respectively. Results of the 19972000 runs have been published, thus completing our experiment for µ
+
. Data analysis for the 2001 run for µ
is currently in progress. To provide measurement of a
µ
= ½(g 2)
µ
at the same level of accuracy as for a
µ
+ = ½(g 2)
µ
+, we would need one more data-taking run.
PACS Nos.: 31.15Pf, 31.30Jv, 32.10Hq
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In the muon
(
g
-
2
)
experiment at Brookhaven National Laboratory, the spin precession frequency
ω
a
is obtained from a standard
χ
2
minimization fit applied to the time distribution of decay ...electrons. The unusually high accuracy
(
∼
0.5
ppm
)
of the experiment puts stringent requirements on the quality of the fit and the level of understanding of the statistical properties of the fitted parameters. We discuss the properties of the fits and their implications on the derived value for
ω
a
, including estimates of the effect of an imperfect fit function, methods of including additional external information to reduce the error, the effects of splitting the data into many smaller subsets of data, applying different weighting methods to the data using energy information, and various tests of data suitability.
Improved limit on the muon electric dipole moment Bennett, G. W.; Bousquet, B.; Brown, H. N. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
09/2009, Letnik:
80, Številka:
5
Journal Article
Status of the BNL muon (g-2) experiment Prigl, R.; Brown, H.N.; Bunce, G. ...
IEEE transactions on instrumentation and measurement,
04/1999, Letnik:
48, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The muon (g-2) experiment at Brookhaven completed a first run in June and July 1997. The main components of the experiment, which include the superconducting inflector, the superferric storage ring, ...the electrostatic quadrupoles and the lead-scintillating fiber electron calorimeters, have been commissioned satisfactorily. Our first measurement of the ratio R of the spin precession frequency of the positive muon relative to that of a free proton, R=(3.707219/spl plusmn/0.000048)/spl times/10/sup -3/, is in good agreement with the previous CERN measurements for /spl mu//sup +/ and /spl mu//sup -/, and has approximately the same uncertainty as each of these measurements. In spring 1998 a muon kicker was installed and successfully tested in the storage ring magnet and a significant improvement in the knowledge of the muon g-factor is expected from upcoming runs in August 1998 and January 1999.
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