Search for New Physics via Rare Decay Liping Gan

University of North Carolina WilmingtonWilmington, NC, USA

Nov 10, 2009Liping Gan, UNCWContentsPhysics MotivationWhy meson is interesting?000 Suggested experiments at JlabSummary

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWWhy meson is interesting?One of the Goldstone bosons due to spontaneous chiral symmetry breaking

The heaviest member in the octet pseudoscalar mesons

Provide a rich program to investigate evidences of symmetry breaking and the new physics beyond the Standard Model

Liping Gan, UNCW

Some Interesting Rare Decay ChannelsNov 10, 2009Liping Gan, UNCW

ModeBranching RatioPhysics Highlight0 0

Nov 10, 2009Liping Gan, UNCWStudy of 0 0 ReactionThe Origin of CP violation is still a mystery

CP violation is described in SM by the phase in the Cabibbo-Kobayashi-Maskawa quark mixing matrix. A recent SM calculation predicts BR(0 0)

Nov 10, 2009Liping Gan, UNCWStudy of the 0 Decay

A stringent test of the PTh prediction at (p6) levelTree level amplitudes (both (p2) and (p4)) vanish;(p4) loop terms involving kaons are suppressed large mass of kaon (p4) loop terms involving pions are suppressed by G parityThe first sizable contribution comes at (p6) levelA long history that experimental results have large discrepancies with theoretic predictions. Current experimental limits in PDG is BR(0 )

Nov 10, 2009Liping Gan, UNCWTheoretical Status on 0 Average of PTh 0.42 By E. Oset et al.

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWHistory of the 0 MeasurementsA long standing puzzle is still un-settled.After 1980

Liping Gan, UNCW

Liping Gan, UNCWHigh Energy ProductionGAMS Experiment at Serpukhov D. Alde et al., Yad. Fiz 40, 1447 (1984)Experimental result was first published in 1981The s were produced with 30 GeV/c - beam in the -pn reaction Decay s were detected by lead-glass calorimeter Major Background-p 00n 000

Final result: (0 ) = 0.840.17 eV

Liping Gan, UNCW

Low energy production CB experiment at AGS

S. Prakhov et al. Phy.Rev.,C78,015206 (2008)The s were produced with 720 MeV/c - beam through the -pn reactionDecay s energy range: 50-500 MeV Final result:

(0 ) = 0.2850.0310.061 eV

Nov 10, 2009Liping Gan, UNCW 000

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWCB Data Analysis II N. Knecht et al. phys. Lett., B589 (2004) 14 Final result

(0)=0.320.15 eV

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWLow Energy Production Continue KLOE experiment B. Micco et al., Acta Phys. Slov. 56 (2006) 403Produce through e+e- collision at s~1020 MeVThe decay 0proceeds through: , 0, 0 Final result:(0)=0.1090.0350.018 eV

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWWhat can be improved at 12 GeV Jlab?High energy tagged photon beam to reduce the background from 30Lower relative threshold for -ray detectionImprove calorimeter resolution Tag by recoiled particles to reduce non-resonance 00 backgroundHigh resolution, high granularity Calorimeter Higher energy resolution improve 0invariance massHigher granularity better position resolution and less overlap clustersLarge statistics to provide a precision measurement of Dalitz plot

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWSuggested Experiments in Hall D at JlabPhoton TaggerGlueXFCAL produced on LH2 target with 11 GeV tagged photon beam +p +p

Tag by measuring recoil p with GlueX detector

Forward calorimeter to detect multi-photons from the decay

Simultaneously measure the 0, 00:

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWKinematics of Recoil Proton Polar angle ~55o-80o

Momentum ~300-1400 MeV/cAngle (Deg)Recoil Pp vs (Deg)Recoil p (Deg) vs Pp (GeV)

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWReconstructed Missing Mass by GlueX Det.E=11.5 GevP/P=1.5%=7 mradMissing Mass (GeV)=43 MeV

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWInvariant Mass ResolutionPWOPb glass=15 MeV=6.9 MeV=3.2 MeV=6.6 MeVMM0M0M

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWS/N Ratio vs. Calorimeter GranularityPWOdmin=4cmS/N=1.4Pb Glassdmin=8cmS/N=0.024

Liping Gan, UNCW

Nov 10, 2009Liping Gan, UNCWRate EstimationThe production rate: LH2 target length L=30cm, =0.0708 g/cm3

The +p+p cross section ~1 b Photon beam intensity N~1.5x107 Hz

The 0 detection rate: BR(0 )~4x10-4 , detection efficiency ~11.4%

Liping Gan, UNCW

SummaryJlab 12 GeV with GlueX setup will provide a great opportunity for precise measurements of various rare decays to test P, CP and C symmetries, and search for new physics beyond the Standard Model

Propose simultaneous measurements on BR(0) and BR( 00) will test the PTh prediction, P and CP symmetries.

Three experimental techniques will be combined:

A 12 GeV high intensity tagged photon beam to produce s.

Tag s by measuring recoil p with GlueX detector to reduce the p 00p background

High resolution and high granularity calorimeter to reduce the 000 background

The EndNov 10, 2009Liping Gan, UNCW

Liping Gan, UNCW

*********************