29 June 2002Emmanuel Monnier - C.P.P.Marseille, U. of Chicago BEACH2002 1 Review of Hyperon in KTeV and other recent results Hyperon beta decays Hyperon

29 June 2002 Emmanuel Monnier - C.P.P.Marseille, U. of Chicago BEACH2002

1

Review of Hyperon in KTeV

and other recent results

Hyperon beta decays Hyperon radiative decays Kaons rare decays Conclusions

(on behalf of the KTeV collaboration)


2

The KTeV Collaboration

E. Cheu, J. Hamm, S.A. Tagger, J. Wang - University of Arizona

K. Arisaka, W. Slater, A. Tripathi, S.E.Turner - University of California, Los Angles

R. Barbosa, C. Escobar, P. Gouffon, R. Zukanovich-Funchal - University of Campaninas/University of Sao Paulo

E. Blucher, C. Bown, S. Bright, A. Glasov, G. Graham, J. Graham, R. Kessler, E. Monnier, V. Prasad, B. Quinn, A. Roodman, P.S. Shawhan, N. Solomey, Y.W. Wah, B. Winstein, R. Winston, E. Zimmerman - University of Chicago

A. R. Barker, J. LaDue, P. Mikelsons, U. Nauenberg, P.A. Toale, J.-Y. Wu - University of Colorado, Boulder

E. C. Swallow - Elmhurst College

L. Bellantoni, R. Ben-David, G.J. Bock, S. Childress, R. Coleman, M. B. Crisler, R. Ford, Y. B. Hsiung, D. A. Jensen, P.L. Mcbride, H. Nguyen, V. O’Dell, M. Pang, R. Pordes, E. Ramberg, R. E. Ray, P. Shanahan, R. Tschirhart, H. B. White, J. WhitmoreFermi National Laboratory

K. Hanagaki, S. Hidaka, T. Nakaya, M. Sadamoto, K. Senyo, I. Suzuki, T. Yamanaka - Osaka University

A. Bellavance, M. D. Corcoran - Rice University

I. Albuquerque, S. Averitte, J. Belz, D.R. Bergman, E. Halkiadakis, A. Lath, S. Schnetzer, S. Somalwar, R. L. Stone, R. Tesarek, G. B. Thomson - Rutgers University

M. Arenton, G. Corti, B. Cox, A. Golossanov, K. Hagan, V. Jejer, S. Ledovskoy, A. P. McManus, K. Nelson - University of Virginia

A.Alavi_Harati, T. Alexopulos, A. R. Erwin - University of Wisconsin, Madison


3

The KTeV detector

●High resolution CsI calorimeterσE/E<1% at <Eγ>=10GeV, π/e>700

●High resolution spectrometerChamber resolution: ~100 µm

●Large TRDRejection π/e>200

●Photon veto

●Intense beam on BeO target5x1012 protons/mn kaons, hyperons


4

Data taking periods


5

KTeV Hyperon Program

●Hyperon beta decays: ●ee and (+ anti mode)

●Hyperon radiative decays●eep

●parameters (lifetime, mass)

●Rare decay search,(S=2)●p


6

●2 neutral clusters:()

●2 tracks:(p)

●1 high momentum track: (p)


7

Allowed beta decays

n p

(red arrows)


8

ee

Signal = 626Signal = 626 +/-+/- 25 events25 events

Background = 60Background = 60 +/- +/- 8 events 8 events

0L

-00

K

pe ,

background

ev

* KTeV first measured B.R = (2.71* KTeV first measured B.R = (2.71 ++ 0.22 0.22 ++ 0.31) x 100.31) x 10-4-4 PRL 82; 3751; (1999) PRL 82; 3751; (1999)

Theoretical (SU3) predicted B.R = (2.61 Theoretical (SU3) predicted B.R = (2.61 ++ 0.11) x 100.11) x 10 -4 -4

B.R = (2.54B.R = (2.54 + + 0.11 0.11 + + 0.16) x 100.16) x 10-4-4 -- --Stat SysStat Sys

--

--

*

--

pee

p

_

_


9

Baryon beta decay

● A(pA(pAA) ) B(p B(pBB) + l + ) + l + q = pq = pAA - p - pBB

● Matrix element:Matrix element:M = 2 = 21/21/2 G G <<B B |J|JAAuul l (p(pll) ) vv (p (p))

● V-A currentV-A current

<<BB |J |JAA = u = uB B {{ff11(q(q22)) + i + i ff22(q(q22)/)/MMAA qqv v + + ff33(q(q22)/)/MMAA q q

+ + gg11(q(q22)) + i + i gg22(q(q22)/)/MMAA qqv v + + gg33(q(q22)/)/MMAA q q

uuAA

● =0.98 for p


10

g1/f1 = 1.32 ± 0.210.17(stat) ± 0.05(syst)

f2/f1 = 2.0 ± 1.2 ± 0.5


11

ee and ee (99)_ ___

1220 ee 105 ee

_ _

KTeV preliminary

KTeV preliminary


12

●From 97 data set: 5 Evts

●Normalisation: ee

● Br=(3.5 ± 2.01.6(stat) ± 0.5

1.0(syst))10-6

● 99+97 not enough for form factor,

● Need few hundreds

_

99 data

Mass (p+0)

Mas

s (

+0-

)

• Correct Charge• Wrong Charge• Final Candidates


13

Events with:●2 photons

(cluster)● (2 tracks)●mass constraint● from target

M (GeV/c2)

M (GeV/c2)


14

In the peak:●4045 events●804 background●Norm:

●BR((3.34±.05±.09)x10-3

M (GeV/c2)


15

= -0.63 +/- 0.08 +/- 0.05

Measurement of

●3 steps process

●Depolarisation of 1/3 for

●Phys. Rev. Lett. 86, 3239 (2001).


16

Polarization at 800 GeV

●Reconstruct

●Extract directions x,y,z (in rest frame)

●Ratio for two magnet settings is:

1 + i Pi (cos i)(with i=x,y,z)


17

Polarization results

****

*

*

_


18

evts 33100,1)( N

evts 1063000,130,1)( 0 N

Winter’97 data(Contained 1 cluster data)

00

3-x10)04.094.0()(

)(

oBR

BR

(stat only)

3PDG 10x]16.006.1[BR

Preliminary BR


19

ee

KTeV preliminary


20

KTeV preliminary


21

Kaon rare decay in KTeV

●Results from 1997 data

●Now combined analysis

●2.5 to 3 times more data

●New combined results


22

●Double dalitz decay

●Angular distributions sensitive to Scalar/pseudoscalare coupling

●ee masses linked to form factors

●Normalisation is KL-ooo with 2 o dalitz decay

●97: 10506 signal events 52446 normalisation events

●99: 17448 signal events 79640 normalisation events

●97+99: 27954 signal / 132086 norm B(o-e+e-e+e-)/B(o-e+e-)2

= 0.2252±0.0015±0.0059

B(o-e+e-e+e-)/B(o-) = (3.274±0.022±0.197)x10-5

Form factor analysis ongoing, results soon

o-e+e-e+e- from KL-ooo


23

● angle of ee plane

●(cos2+Csin2)(SM: = -0.18, C = 0)

●No indication of CP violation

Parity analysis of o**

coupling

KTeV preliminary


24

KL-+-

● Br(KL-+-)=(3.62±0.04±0.08)x10-7

● Normalized to KL-+-o

● K*=-0.160-0.028

+0.026


25

KL-e+e-

●Br(KL-e+e-)=

(10.13±0.04±0.06±0.29)x10-6

●Normalized to KL-oooD

●93383 Sig. / 5306073 Norm.

●K*=-0.192±0.011±0.009(syst)


26

Result on K*


27

KL-e+e-

+-

●Normalized to KL-+-oD

●93383 Sig. / 5306073 Norm.

●Br(KL-e+e-+-)=

(2.61±0.23±0.18)x10-9

(VMD prediction is 2.34x10-9 )


28

KL-e+e-

+-

●No CP violation effect in angular distribution

●Search for lepton flavor violation:

●Br(KL-e±e±±±)<(4.12)x10-11

(90% C.L., preliminary)

●Form factor analysis soon


29

Other recent results

●KL-+-e+e-

●5056 ± 71 events

●A=(13.3±1.4±1.0)% (preliminary)

●+ Vector form factor parameters

●KL-o±e-+ :

●Br(KL-o±e-+)<(3.34)x10-10

(90% C.L., preliminary)


30

Conclusion

●KTeV has produced many results●Hyperon decays

●Kaon rare decays

●High statistic modes

●But KTeV has still a lot to produced from the 99 data set and many results will come out soon…

Documents

29 June 2002Emmanuel Monnier - C.P.P.Marseille, U. of Chicago BEACH2002 1 Review of Hyperon in KTeV and other recent results Hyperon beta decays Hyperon