Decays K L,S pi 0 pi 0 gamma and K L,S pi 0 pi 0 e + e - as probes of chiral dynamics PDF Download

Author: Patrick Heiliger
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Category :
Languages : en
Pages : 20

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Languages : en
Pages : 4

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The KTeV E799 experiment has conducted a search for the rare decay K{sub L} 2![pi]°°[gamma] via the topology K{sub L} 2![pi]°[pi]°{sub D}[gamma] (where [pi]°{sub D} 2![gamma]ee−). Due to Bose statistics of the [pi]° pair and the real nature of the photon, the K{sub L} 2![pi]°[pi]°[gamma] decay is restricted to proceed at lowest order by the CP conserving direct emission (DE) of an E2 electric quadrupole photon. The rate of this decay is interesting theoretically since chiral perturbation theory predicts that this process vanishes at level O(p4). Therefore, this mode probes chiral perturbation theory at O(p6). In this paper we report a determination of an upper limit of 2.43 x 10−7 (90% CL) for K{sub L} 2![pi]°[pi]°[gamma]. This is approximately a factor of 20 lower than previous results.

Author: David Edward Smith
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Category :
Languages : en
Pages : 141

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This thesis describes a search for the rare decay K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{gamma} using data from the KTeV experiment, using the topology K{sub L} {yields} {pi}{sup 0}{pi}{sub D}{sup 0}{gamma} (where {pi}{sub D}{sup 0} {yields} {gamma}e{sup +}e{sup -}). Due to Bose statistics and the real nature of the photon, the K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{gamma} decay can proceed at lowest order only by the Cp conserving direct emission of an E2 photon. The decay vanishes to O(p{sup 4}) in chiral perturbation theory and is a probe of the theory to the sixth order. The primary background to this decay consists of K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{pi}{sub D}{sup 0} events with one lost photon. The upper limit for the decay K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{gamma} presented in this thesis is 2.32 x 10{sup -7} at the 90% confidence level. This upper limit was derived from both 1997 and 1999 data, using a blind analysis. The upper limit was derived from a Feldman-Cousins method, based on a weighted total of 0.53 data events in the signal region with an expected K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{pi}{sub D}{sup 0} background of 0.37 {+-} 0.28 events. The previous upper limit for this decay was 5.6 x 10{sup -6} at the 90% confidence level.

Author: Patrick Heiliger
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Languages : de
Pages : 20

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Author: David Edward Smith
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Languages : en
Pages : 364

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Author: Vaia Papadimitriou
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Category : Kaons
Languages : en
Pages : 572

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Languages : en
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We present a measurement of the time-dependent CP-violating asymmetries in B[sup 0] [yields] K*[sup 0][gamma](K*[sup 0] [yields] K[sub S][sup 0][pi][sup 0]) decays based on 124 million [Upsilon](4S) [yields] B[bar B] decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. In a sample containing 105 [+-] 14 signal decays, we measure S[sub K*[sub [gamma]]] = 0.25 [+-] 0.63 [+-] 0.14 and C[sub K*[sub [gamma]]] = -0.57 [+-] 0.32 [+-] 0.09, where the first error is statistical and the second systematic.

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Languages : en
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With the E731 apparatus at Fermilab, we have simultaneously collected 6859 K(L) and K(S) decays into pi+pi-gamma. Using our sample of over 370000 pi+pi- decays for normalization we have determined that the ratio GAMMA(K0 --> pi+pi-gamma)/GAMMA(K0 --> pi+pi- ) is (23.0 +/- 0.7) x 10( -3) for K(L) and (7.10 +/- 0.22) x 10( -3) for K(S), for photon energies greater than 20 MeV in the kaon center of mass. After removing the inner-bremsstrahlung contribution, we find that the photon energy spectrum of the direct emission decay of the K(L) is consistent with the presence of a vector meson propagator in the form factor.

Author: James Paul Morris
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ISBN:
Category :
Languages : en
Pages : 153

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Abstract: The Standard Model is the best current description of fundamental interactions and particles; however, the Standard Model has certain shortcomings which have driven particle physicists for the last 30 years to search for phenomena which provide evidence for the next theory beyond the Standard Model. To this end, using the BaBar detector, we search for evidence of the rare decay D* -> D0[pi];D0->[gamma][gamma]. The branching fraction of this decay is enhanced up to 200 times the standard model prediction in certain beyond-the-Standard-Model theories. A measurement of a significant branching fraction would provide evidence for a new theory of particle physics. We describe our search for this rare decay and an improved measurement of the associated decay, B(D0-> [pi]0 [pi]0) using an integrated luminosity corresponding to 470.5 fb−1 of e e− data collected by the BaBar detector at the PEP-II asymmetric ee− collider at SLAC from 1999-2007. We place an upper limit of B(D0->[gamma][gamma]) 2.51 X 10−6 at 90% confidence level and find B(D0-[pi]0[pi]0) = (8.4 " 0.1 " 0.4 " 0.3) X 10−4.

Author: Robert W. Garland
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ISBN:
Category :
Languages : en
Pages : 118

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