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Observation of the Decay K{sup +} yields P{sup +} v...

Description: We have observed 1 event consistent with the signature expected of the rare decay of a positive kaon to a positive pion and a neutrino anti-neutrino pair. In the examined momentum region of 211 to 230 MeV/c in the center of mass of the kaon we estimated the backgrounds to be about 0.08 &plusmn; 0.03 events. From this observation we estimate the branching ratio to be 4.2<SUP>+9.7</SUP><SUB>-3.5</SUB> x 10<SUP>-10</SUP>. In this presentation I will explain the experiment, and the analysis techniques. I will also discuss the expected improvements in the near future from the analysis of new data sets.
Date: May 21, 1999
Creator: Diwan, M.V.
Partner: UNT Libraries Government Documents Department

Evidence for {Kappa}{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}}

Description: The first observation of the decay {Kappa}{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} has been reported. The E787 experiment presented evidence for the {Kappa}{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} decay, based on the observation of a single clean event from data collected during the 1995 run of the AGS (Alternating Gradient Synchrotron at Brookhaven National Laboratory). The branching ratio indicated by this observation, {Beta}({Kappa}{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}}) = 4.2{sub {minus}3.5}{sup +9.7} {times} 10{sup {minus}10}, is consistent with the Standard Model expectation although the central experimental value is four times larger. The final E787 data sample, from the 1995--98 runs, should reach a sensitivity of about five times that of the 1995 run alone. A new experiment, E949, has been given scientific approval and should start data collection in 2001. It is expected to achieve a sensitivity of more than an order of magnitude below the prediction of the Standard Model.
Date: December 31, 1998
Creator: Kettell, S.
Partner: UNT Libraries Government Documents Department

919: Evidence for K{sup +} {r_arrow} {pi}{sup +} {nu}{bar {nu}} from E787

Description: A collaboration from KEK, INS, Osaka, TRIUMF, Princeton, and BNL is currently running E787 at the AGS. The experiment is designed primarily to search for the rare decay K{sup +} {yields} {pi}{sup +}{nu}{bar {nu}}, with an expected branching ratio of {approximately} 10{sup {minus}10}. The authors report evidence that they have observed this decay. They also discuss the future outlook for the experiment.
Date: December 1, 1997
Creator: Frank, J.S. & Collaboration, E787
Partner: UNT Libraries Government Documents Department

Scaling between K{sup +} and proton production in nucleus-nucleus collisions

Description: An empirical scaling involving the production of strange particle K{sup +} and protons has been observed at each rapidity over a large range covered by the E-802 spectrometer in reactions from minimum biased p+Be to central Si+Au at 14.6 A-GeV/c. This scaling has implications for the temporal evolution in nucleus-nucleus collisions.
Date: March 1, 1995
Creator: Chen, Ziping & Chasman, C.
Partner: UNT Libraries Government Documents Department

RARE K+ DECAYS FROM EXPERIMENT E787.

Description: This paper presents the latest results from experiment E787, at Brookhaven National Laboratory, on K{sup +} {r_arrow} {pi}{sup +} {nu}{bar {nu}} and radiative K{sup +} decays. The result for K{sup +} {r_arrow} {pi}{sup +} {nu}{bar {nu}} uses data collected in runs taken during 1995, 1996 and 1997. In addition, they discuss plans for future measurements of K{sup +} {r_arrow} {pi}{sup +} {nu}{bar {nu}}.
Date: October 9, 2000
Creator: JAIN,V.
Partner: UNT Libraries Government Documents Department

A kaon physics program at the Fermialb Main Injector

Description: In this paper we describe a triad of kaon experiments which will form the foundation of a kaon physics program at Fermilab in the Main Injector era. These three experiments; KAMI, CKM and CPT, span the range of experiment types discussed above. KAMI will use the existing neutral kaon beam and the KTeV detector as the basis of a search for the Standard Model ultra rare decay K{sub L} {yields} {pi}{sup 0}{nu}{anti {nu}} decay mode is by far the theoretically cleanest measurement of the Standard Model parameter responsible for CP violation. CKM will measure the analogous charged kaon decay mode. Together these two experiments will determine the Standard Model contribution to CP violation independent of the B meson sector. The Standard Model parameters controlling CP violation must be observed to be the same in the K and B meson sectors in order to confirm the Standard Model as the sole source of CP violation in nature. CPT is a hybrid beam experiment using a high purity K{sup +} beam to produce a pure K{sub 0} beam in order to search for violation of CPT symmetry at a mass scale up to the Planck mass. CPT also will measure new CP violation parameters to test the Standard Model and search for rare K{sub S} decays. The Fermilab infrastructure for such a physics program largely already exists. The Main Injector will be an existing accelerator by late 1998 with beam properties comparable to any of the previous ``kaon factory`` proposals. The KTeV detector and neutral kaon beamline are unsurpassed in the world and were originally designed to also operate with the 120 GeV Main Injector beam as KAMI. The Fermilab Meson laboratory was originally designed as an area for fixed target experiments using 200 GeV proton beams. The charged kaon beam experiments ...
Date: November 1, 1997
Creator: Cooper, Peter
Partner: UNT Libraries Government Documents Department

Observation of the decay K{sup +} {r_arrow} {pi}{sup +} {nu}{bar {nu}}

Description: We have observed 1 event consistent with the signature expected of the rare decay of a positive kaon to a positive pion and a neutrino anti-neutrino pair. In the examined momentum region of 211 to 230 MeV/c in the center of mass of the kaon we estimated the backgrounds to be about 0.08 {+-} 0.03 events. From this observation we estimate the branching ratio to be 4.2{sub {minus}3.5}{sup +9.7} x 10{sup {minus}10}. In this presentation I will explain the experiment, and the analysis techniques. I will also discuss the expected improvements in the near future from the analysis of new data sets.
Date: January 5, 1999
Creator: DIWAN,M.B.
Partner: UNT Libraries Government Documents Department

Evidence for K{sup +} {r_arrow} {pi}{sup +} {nu}{anti {nu}}

Description: The decay K{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} has been observed for the first time. The E787 experiment has presented evidence for the K{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}} decay, based on the observation of a single clean event from data collected during the 1995 run of the AGS (Alternating Gradient Synchrotron at Brookhaven National Laboratory). The branching ratio indicated by this observation, B(K{sup +} {r_arrow} {pi}{sup +}{nu}{anti {nu}}) = 4.2{sub {minus}3.5}{sup +9.7} {times} 10{sup {minus}10}, is consistent with the Standard Model expectation although the central experimental value is four times larger. The final E787 data sample, from the 1995--99 runs, should reach a sensitivity of about eight times that of the 1995 run alone. A new experiment, E949, has been approved to run, starting in the year 2000, and is expected to achieve a sensitivity of more than an order of magnitude below the prediction of the Standard Model.
Date: December 31, 1998
Creator: Kettell, S.; Collaboration, E787 & Collaboration, E949
Partner: UNT Libraries Government Documents Department

Rare decays experimental summary and prospects

Description: I review the status and future prospects of searches for forbidden and highly kaon suppressed decays. This workshop comes as we are poised at the threshold of a new generation of rare K decay experiments. There are new experiments running or about to run at KEK, BNL, FNAL, and CERN. In another year or so these will be joined by the KLOE experiment at DA{Phi}NE. The good news is that it`s a very exciting time. The bad news, at least for a reviewer, is that there aren`t too many new results. Thus I`ll be giving a little more attention than usual to what the experimenters expect to do. My discussion of rare K decays covers processes that are forbidden in the Standard Model, those that highly suppressed and to a smaller extent, those that are merely discouraged.
Date: December 31, 1996
Creator: Littenberg, L.
Partner: UNT Libraries Government Documents Department

Search for T-violation in K{sub {mu}3} decay

Description: We have designed a new experiment (E923) at the BNL-AGS to search for the T-violating polarization of the muon normal to the decay plane of the K{sup +} {yields} {mu}{sup +}{pi}{sup 0}{nu} decay. The experiment aims to search for T-violation beyond the Standard Model; such a search is motivated by the need for a stronger CP violation source to account for the baryon asymmetry of the Universe. The experiment will be performed with in-flight decays from an intense (2 x 10{sub 7} K{sup +}/sec) 2 GeV/c separated K{sup +} beam in an existing beam-line at the AGS. We expect to analyze more than 10{sup 9} events to obtain the sensitivity of {delta}P{sub 2} = {+-} 0.00013 at 1 {sigma}, corresponding to the sensitivity of {+-}0.0007 to Im{xi}, an improvement by 40 over the present limit on the same measurement.
Date: January 8, 1998
Creator: Diwan, M.V.
Partner: UNT Libraries Government Documents Department

(S{sub 3}){sup 3} theories of flavor

Description: The author presents a supersymmetric theory of flavor based on the discrete flavor group (S{sub 3}){sup 3}. The model can account for the masses and mixing angles of the standard model, while maintaining sufficient sfermion degeneracy to evade the supersymmetric flavor problem. The author demonstrates that the model has a viable phenomenology and makes one very striking prediction: the nucleon decays predominantly to Kl where l is a first generation lepton. He shows that the modes n {yields} K{sup 0}{bar {nu}}{sub e}, p {yields} K{sup +}{bar {nu}}{sub e}, and p {yields} K{sup 0}e{sup +} occur at comparable rates, and could well be discovered simultaneously at the SuperKamiokande experiment.
Date: July 1, 1996
Creator: Carone, C.D.
Partner: UNT Libraries Government Documents Department

Extracting forward strong amplitudes from elastic differential cross sections

Description: The feasibility of a model-independent extraction of the forward strong amplitude from elastic nuclear cross section data in the Coulomb-nuclear interference region is assessed for {pi} and K{sup +} scattering at intermediate energies. Theoretically-generated ''data'' are analyzed to provide criteria for optimally designing experiments to measure these amplitudes, whose energy dependence (particularly that of the real parts) is needed for disentangling various sources of medium modifications of the projectile-nucleon interaction. The issues considered include determining the angular region over which to make the measurements, the role of the most forward angles measured, and the effects of statistical and systematic errors. We find that there is a region near the forward direction where Coulomb-nuclear interference allows reliable extraction of the strong forward amplitude for both pions and the K{sup +} from .3 to 1 GeV/c.
Date: July 1, 2001
Creator: Chen, C.M.; Ernst, D.J. & Johnson, Mikkel B.
Partner: UNT Libraries Government Documents Department

Review of charm lifetimes

Description: A review of the latest experimental results on charm particle lifetimes is presented. The most significant update is that the D{sub s}{sup +} lifetime is conclusively larger than the D{sup 0} lifetime and signifies that W-exchange/W-annihilation contributions are large. Using new high statistics data on D{sup +} {r{underscore}arrow} K{sup +}{pi}{sup +}{pi}{sup {minus}} together with the D{sub s}{sup +} lifetime and some assumptions, one can phenomenologically extract the strength of the W-exchange contribution in D{sup 0} decays and of W-annihilation in D{sub s}{sup +} decays. These are larger than or at the limit of theoretical expectations using QCD-based operator production expansion techniques.
Date: January 6, 2000
Creator: Cheung, H.W.K.
Partner: UNT Libraries Government Documents Department

Elastic charge form factors for K

Description: The elastic charge form factors for the charged K{sup +} and neutral K{sup 0} are presented. The model employed makes use of solutions of the coupled Bethe-Salpeter and Schwinger-Dyson equations. This covariant model, which provides good predictions for the pion's elastic charge and transition form factor, has been presented elsewhere and will be briefly outlined here. The results for the kaon are in good agreement with the available data and can serve as an eventual guide in the interpretation of the approved CEBAF experiment E-93-018. The Q{sup 2} dependent K{sup 0} results suggest a new area for experimental exploration.
Date: January 1994
Creator: Buck, W. W.; Williams, R. A. & Ito, H.
Partner: UNT Libraries Government Documents Department

Recent results from E866 and scaling between K{sup +} and protons in E802

Description: E866 is designed to study Au+Au reactions at 11.6 A{center_dot}GeV/c with two spectrometers, one upgraded from E802 and another built to cope with the large multiplicity in central Au+Au collisions at forward angles in the laboratory frame. Furthermore, new global detectors have been implemented to gain insight into the reaction dynamics and enable studies of possible collective effects. The first half of this report presents the recent preliminary results for rapidity distributions of protons and produced mesons in central Au+Au collisions. The shape of m{sub t}spectra of pions is discussed. The second half of this report discusses some insight into K{sup +} production in conjunction with proton production in reactions induced by light ion beams, namely from proton to Si beams.
Date: May 1, 1995
Creator: Chen, Ziping & Collaboration, E802
Partner: UNT Libraries Government Documents Department

Observation of CP Violation in B0 to K+pi- and B0 to pi+pi-

Description: The authors report observations of CP violation in the decays B{sup 0} {yields} K{sup +}{pi}{sup -} and B{sup 0} {yields} {pi}{sup +}{pi}{sup -} in a sample of 383 million {Upsilon}(4S) {yields} B{bar B} events. They find 4372 {+-} 82 B{sup 0} {yields} K{sup +}{pi}{sup -} decays and measure the direct Cp-violating charge asymmetry {Alpha}{sub K{pi}} = -0.107 {+-} 0.018(stat){sub -0.004}{sup +0.007}(syst), which excludes the CP-conserving hypothesis with a significance of 5.5 standard deviations. In the same sample they find 1139 {+-} 49 B{sup 0} {yields} {pi}{sup +}{pi}{sup -} decays and measure the CP-violating asymmetries S{sub {pi}{pi}} = -0.60 {+-} 0.11(stat) {+-} 0.03(syst) and C{sub {pi}{pi}} = -0.21 {+-} 0.09(stat) {+-} 0.02(syst). CP conservation in B{sup 0} {yields} {pi}{sup +}{pi}{sup -} (S{sub {pi}{pi}} = C{sub {pi}{pi}} = 0) is excluded at a confidence level 1-C.L. = 8 x 10{sup -8}, corresponding to 5.4 standard deviations.
Date: March 14, 2007
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department

Observation of Decays $B^0\to D_s^{(*)+}\pi^-$ and$B^0\to D_s^{(*)-}K^+$

Description: The authors report the observation of decays B{sup 0} {yields} D{sub s}{sup (*)+} {pi}{sup -} and B{sup 0} {yields} D{sub s}{sup (*)-} K{sup +} in a sample of 230 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} events recorded with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. They measure the branching fractions {Beta}(B{sup 0} {yields} D{sub s}{sup +}{pi}{sup -}) = (1.3 {+-} 0.3(stat) {+-} 0.2(syst)) x 10{sup -5}, {Beta}(B{sup 0} {yields} D{sub s}{sup -}K{sup +}) = (2.5 {+-} 0.4(stat) {+-} 0.4(syst)) x 10{sup -5}, {Beta}(B{sup 0} {yields} D*{sub s}{sup +} {pi}{sup -}) = (2.8 {+-} 0.6(stat) {+-} 0.5 (syst)) x 10{sup -5}, and {Beta}(B{sup 0} {yields} D*{sub s}{sup -} K{sup +}) = (2.0 {+-} 0.5(stat) {+-} 0.4(syst)) x 10{sup -5}. The significance of the measurements to differ from zero are 5, 9, 6, and 5 standard deviations, respectively.
Date: April 19, 2006
Creator: Aubert, B.
Partner: UNT Libraries Government Documents Department

Evidence for a Narrow Near-Threshold Structure in the $J/\psi\phi$ Mass Spectrum in $B^+\to J/\psi\phi K^+$ Decays

Description: Evidence is reported for a narrow structure near the J/{psi}{phi} threshold in exclusive B{sup +} {yields} J/{psi}{phi}K{sup +} decays produced in {bar p}p collisions at {radical}s = 1.96 TeV. A signal of 14 {+-} 5 events, with statistical significance in excess of 3.8 standard deviations, is observed in a data sample corresponding to an integrated luminosity of 2.7 fb{sup -1}, collected by the CDF II detector. The mass and natural width of the structure are measured to be 4143.0 {+-} 2.9(stat) {+-} 1.2(syst) MeV/c{sup 2} and 11.7{sub -5.0}{sup +8.3}(stat) {+-} 3.7(syst) MeV/c{sup 2}.
Date: March 1, 2009
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, Jahred A.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
Partner: UNT Libraries Government Documents Department

Searches for Rare Leptonic and Semileptonic Charm Decays at BaBar

Description: Recent results from leptonic and semi-leptonic charm decays at the BABAR B-factory are presented. The measurement of f{sub D{sub s}} from the D{sub s}{sup +} {yields} {mu}{sup +}{nu} channel is presented. Form-factor studies from the D{sup 0} {yields} K{sup +}e{sup -}{bar {nu}}{sub e} channel are described along with a search for flavor-changing neutral-current X{sub c}{sup +} {yields} h{sup +}{ell}{sup +}{ell}{prime}{sup -} decays.
Date: January 17, 2007
Creator: Jackson, Paul D. & U., /Ohio State
Partner: UNT Libraries Government Documents Department