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Search for Pomeron--Pomeron-2$pi$ events in 205 GeV/c $pi$$sup -$p interactions

Description: Pomeron- pomeron-2 pi vertices were sought in the reaction pi /sup -/p yields pi /sup -/ pi /sup +/ pi /sup -/p at 205 GeV/c. From a sample of 1 86 of these events, about 2/3 were extracted for which the rapidity ordering of the four outgoing particles makes them candidates for the double-Pomeron exchange process (i.e., the fastest and the slowest particle are respectively a pi /sup -/ and a proton). A separation from single-Pomeron processes was attempted with the help of a rapidity triangle plot. The number of possible double-Pomeron-type events was also estimated from a Regge-propagator fit to the nonhomogeneous distribution of the events within this triangle. The number of such events obtained by either method gives a cross section upper limit of 85 mu b for double-Pomeron exchange, consistent with the predictions of a pion-pole dominance model. (auth)
Date: August 1, 1973
Creator: Chew, D.M.; Abrams, G.S. & Bingham, H.H.
Partner: UNT Libraries Government Documents Department

Diffraction dissociation in 205 GeV/c $pi$$sup -$p two- and four-prong interactions

Description: From meeting of the division of particles and fields; Berkeley, California, USA (13 Aug 1973). Data are presented on diffraction dissociation in pi /sup -/p yields pi /sup -/p and pi /sup -/p yields pi /sup -/ pi /sup - / pi /sup +/p interactions at 205 GeV/c. Mass spectra and cross sections for pion dissociation and nuclear dissociation are presented. (LBS)
Date: August 10, 1973
Creator: Abrams, G.S.; Bingham, H.H. & Chew, D.M.
Partner: UNT Libraries Government Documents Department

First results from Mark II at SPEAR

Description: First results from the SLAC-LBL Mark II magnetic detector at SPEAR are presented. The performance of the detector is discussed and preliminary results are given on inclusive baryon production R/sub p + anti p/, R/sub ..lambda.. + anti ..lambda../, on decay modes of the D mesons and on two-photon production of eta' mesons.
Date: May 1, 1979
Creator: Abrams, G.S.; Alam, M.S. & Blocker, C.A.
Partner: UNT Libraries Government Documents Department

Results on two-photon interactions from Mark II at SPEAR

Description: Preliminary results on two-photon interactions from the SLAC-LBL Mark II magnetic detector at SPEAR are presented. The cross section for eta' production by the reaction e/sup +/e/sup -/ ..-->.. e/sup +/e/sup -/ eta' has been measured over the beam energy range from 2 to 4 GeV. The radiative width GAMMA/sub ..gamma gamma../(eta') has been determined to be 5.8 +- 1.1 keV (+- 20% systematic uncertainty). Upper limits on the radiative widths of the f(1270), and A/sub 2/(1310) and f'(1515) mesons have been determined.
Date: October 1, 1979
Creator: Abrams, G.S.; Alam, M.S. & Blocker, C.A.
Partner: UNT Libraries Government Documents Department

Results from the Mark II dectetor at SPEAR: SLAC-LBL Mark II collaboration

Description: Some recent results are presented from the Mark II detector at SPEAR: observation of some new D meson decay modes, including the Cabibbo suppressed K/sup -/K/sup +/ and ..pi../sup -/..pi../sup +/ modes, measurements of the rho ..nu.. and ..pi nu.. decays of the tau, and some new data on psi decays. 17 references.
Date: June 1, 1979
Creator: Abrams, G.S.; Alam, M.S. & Blocker, C.A.
Partner: UNT Libraries Government Documents Department

Some first results from the Mark II at SPEAR. [Branching ratio, cross sections]

Description: Preliminary results are given from the Mark II experiment at SPEAR on radiative decays of the psi' (3684) and on inclusive baryon production from 3.67 to 7.4 GeV center-of-mass energy. A 90% confidence level upper limit of 0.12% is given for BR(psi' ..-->.. ..gamma..eta'/sub c/(3455)) x BR(eta'/sub c/(3455 ..-->.. ..gamma..psi)). 10 references.
Date: June 1, 1979
Creator: Abrams, G.S.; Alam, M.S. & Blocker, C.A.
Partner: UNT Libraries Government Documents Department

Backgrounds to the detection of two-body hadronic B decays

Description: We consider backgrounds to the detection of the two-body hadronic decay modes of neutral B mesons and baryons. The largest background is due to the correlated production of pairs of high-p/sub T/ hadrons in the target, but this can be adequately rejected provided the experimental apparatus has sufficient resolution in mass and decay vertex. Another possible source of background arises from the production and decay of charmed and strange particles. Since these particles can travel considerable distances before decaying, they can give rise to backgrounds which may not be rejectable by means of vertex cut. We have simulated several backgrounds from charm, and we find them to be small compared to the expected level of signal. 8 refs., 1 fig., 2 tabs
Date: January 8, 1988
Creator: Kaplan, D.M.; Peng, Jen-Chieh; Abrams, G.S. & Stockdale, I.E.
Partner: UNT Libraries Government Documents Department

Z sup 0 physics from the Mark II at the SLC (SLAC Linear Collider)

Description: The MARK II detector has started to take data at the new SLAC Linear Collider. The novel aspects of the accelerator and of the MARK II are briefly described. Displays of event pictures from some of the early-on data are presented to illustrate the quality of the data. A first presentation of the results of an energy scan near the Z{sup 0} mass that is currently in progress shows the expected resonant enhancement near 91 GeV. 2 refs., 23 figs., 1 tab.
Date: June 1, 1989
Creator: Abrams, G.S. (Lawrence Berkeley Lab., CA (USA))
Partner: UNT Libraries Government Documents Department

Transverse wakefield control and feedback in the SLC (SLAC Linear Collider) linear

Description: Transverse wakefields in the linac of the SLAC Linear Collider (SLC) have been observed to enlarge the effective emittance of beams which are not properly centered in the accelerating structure. A fast feedback system has been constructed to minimize the enlargement under changing conditions by controlling the beam launching parameters. Theoretical aspects of this transverse feedback system are reviewed as well as the design of the beam sensors, launch controllers, communication equipment and data processing micro-computer. A variety of beam observations have been made. They show that dispersion as well as wakefield effects are important. In the near future the fast transverse feedback system will be beam tested, and algorithms tailored to the noise environment of the SLC will be tried.
Date: January 1, 1987
Creator: Seeman, J.T.; Campisi, I.E.; Herrmannsfeldt, W.; Lee, M.; Petersen, A.; Phinney, N. et al.
Partner: UNT Libraries Government Documents Department

Fast energy and energy spectrum feedback in the SLC Linac

Description: The energies and energy spectra of the positron and electron beams emerging from the SLC Linac must be carefully maintained so that the beams can be transported through the Arcs to the Final Focus without phase space dilution and also to specify the collision energy. A fastback system has been designed and constructed to control these parameters. The energies and energy spectra are measured nondestructively using position monitors and synchrotron radiation width monitors. The controls consist of rf phases in the Damping Rings, SLED timing, and rf amplitude. Theoretical aspects of the feedback process, algorithms, and operational experience are discussed.
Date: January 1, 1987
Creator: Abrams, G.S.; Soderstrom, E.; Seeman, J.T.; Campisi, I.E.; Herrmannsfeldt, W.; Lee, M. et al.
Partner: UNT Libraries Government Documents Department

Fast energy spectrum and transverse beam profile monitoring and feedback systems for the SLC linac

Description: Fast energy spectrum and transverse beam profile monitoring systems have been tested at the SLC. The signals for each system are derived from digitizations of images on phosphor screens. Individual beam bunch images are digitized in the case of the transverse profile system and synchrotron radiation images produced by wiggler magnets for the energy spectrum. Measurements are taken at two-second intervals. Feedback elements have been installed for future use and consist of rf phase shifters to control energy spectrum and dipole correctors to control the beam launch into the linac affecting the transverse beam profile. Details of these systems, including hardware, timing, data acquisition, data reduction, measurement accuracy, and operational experience will be presented. 9 refs.
Date: March 1, 1989
Creator: Soderstrom, E.J.; Abrams, G.S.; Weinstein, A.J.; Brown, R.L.; Gromme, T.E.; Jacobsen, R.G. et al.
Partner: UNT Libraries Government Documents Department

A beam energy analysis and monitoring system for linear accelerators

Description: A model-based beam orbit simulation program has been used successfully to analyze the beam energy errors at the two-mile linear accelerator during commissioning of the SLC system. This simulation program has also been used to develop a nondestructive beam energy error monitoring system. The method of analysis, the simulation program, and a beam energy analysis and monitoring system using expert systems techniques will be described.
Date: February 1, 1988
Creator: Lee, M.J.; Kleban, S.D.; Zambre, Y.B.; Seeman, J.T.; Adolphsen, C.E.; Abrams, G.S. et al.
Partner: UNT Libraries Government Documents Department

Inclusive gamma K0(s) lambda0 and anti-lambda0 production by 205-GeV/c pion proton interactions

Description: Neutral decays and {gamma} conversions have been analyzed in an exposure of the NAL 30 hydrogen bubble chamber to 205 GeV/c pions. This paper presents preliminary results on inclusive cross sections for the production of {Upsilon}'s, K{sub s}{sup 0}'s, {Lambda}{sup 0}'s and {bar {Lambda}}{sup 0}'s by 205 GeV/c {pi}{sup -}p interactions. The experiment was done in the NAL 30 hydrogen bubble chamber. Six hundred and sixty-four neutral decays (or conversions) found in a scan of 3058 {pi}{sup -}p interactions were measured. During measurement, three percent of these events were rejected as not pointing to the primary vertex. Another 29% were discarded by a fiducial volume cut on the neutral vertex.
Date: August 1, 1973
Creator: Bogert, D.; Hanft, R.; Huson, F.R.; Ljung, D.; Pascaud, C.; Pruss, S. et al.
Partner: UNT Libraries Government Documents Department

PERFORMANCE OF THE LEAD/LIQUID ARGON SHOWER COUNTER SYSTEM OF THE MARK II DETECTOR AT SPEAR

Description: The shower counter system of the SLAC-LBL Mark II detector is a large lead/liquid argon system of the type pioneered by Willis and Radekal; however, it differs in most details and is much larger than other such detectors currently in operation, It contains, for example, 8000 liters of liquid argon and 3000 channels of low noise electronics, which is about eight times the size of the system of Willis et al. in the CERN ISR. This paper reports, with little reference to design, on the operation and performance of the Mark II system during approximately a year and a half of operation at the Stanford Linear Accelerator Center's e{sup +}-e{sup -} facility, SPEAR. The design and construction of the system have previously been described and a detailed discussion of all aspects -- design, construction, operation, and performance -- is in preparation.
Date: May 1, 1980
Creator: Abrams, G.S.; Blocker, C.A.; Briggs, D.D.; Carithers, W.C.; Dieterle, W.E.; Eaton, M.W. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the CKM Angle Gamma in B0 to Anti-D0 (D0) K*0 With a Dalitz Analysis of D0 to K(S) Pi+ Pi-

Description: The authors present a measurement of the angle {gamma} of the Unitarity Triangle with a Dalitz analysis of neutral D decays to K{sub S}{pi}{sup +}{pi}{sup -} from the processes B{sup 0} {yields} {bar D}{sup 0}(D{sup 0})K*{sup 0} ({bar B}{sup 0} {yields} D{sup 0}({bar D}{sup 0}){bar K}*{sup 0}) with K*{sup 0} {yields} K{sup +}{pi}{sup -} ({bar K}*{sup 0} {yields} K{sup -} {pi}{sup +}). Using a sample of 371 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at PEP II, they measure the angle {gamma} as a function of r{sub S}, the magnitude of the average ratio between b {yields} u and b {yields} c amplitudes. Combining this result with the available information on r{sub S}, they obtain {gamma} = (162 {+-} 56){sup o} or (342 {+-} 56){sup o} and r{sub S} < 0.55 at 95% probability.
Date: June 9, 2008
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Dalitz Plot Analysis of the Decay B0(B0bar) to K^+/- pi^-/+ pi0

Description: The authors report a Dalitz-plot analysis of the charmless hadronic decays of neutral B mesons to K{sup {+-}}{pi}{sup {-+}}{pi}{sup 0}. With a sample of (231.8 {+-} 2.6) x 10{sup 6}{Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, they measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for B{sup 0} and {bar B}{sup 0} decays and determine the corresponding CP-averaged branching fractions and charge asymmetries. The inclusive branching fraction and CP-violating charge asymmetry are measured to be {Beta}(B{sup 0} {yields} K{sup +}{pi}{sup -}{pi}{sup 0}) = (35.7{sub -1.5}{sup +2.6} {+-} 2.2) x 10{sup -6}, and {Alpha}{sub CP} = -0.030{sub -0.051}{sup +0.045} {+-} 0.055 where the first errors are statistical and the second systematic. They observe the decay B{sup 0} {yields} K*{sup 0}(892){pi}{sup 0} with the branching fraction {Beta}(B{sup 0} {yields} K*{sup 0}(892){pi}{sup 0}) = (3.6{sub -0.8}{sup +0.7} {+-} 0.4) x 10{sup -6}. This measurement differs from zero by 5.6 standard deviations (including the systematic uncertainties). The selected sample also contains B{sup 0} {yields} {bar D}{sup 0}{pi}{sup 0} decays where {bar D}{sup 0} {yields} K{sup +}{pi}{sup -}, and they measure {Beta}(B{sup 0} {yields} {bar D}{sup 0}{pi}{sup 0}) = (2.93 {+-} 0.17 {+-} 0.18) x 10{sup -4}.
Date: September 18, 2008
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prudent, X. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Branching Fractions of the Rare Decays B0 to Ds(*)+pi-,B0 to Ds(*)+rho-, and B0 to Ds(*)-K(*)+

Description: The authors report the measurement of the branching fractions of the rare decays B{sup 0} {yields} D{sub s}{sup (*)+} {pi}{sup -}, B{sup 0} {yields} D{sub s}{sup (*)+} {rho}{sup -}, and B{sup 0} {yields} D{sub s}{sup (*)-} K{sup (*)+} in a sample of 381 x 10{sup 6} {Upsilon}(4S) decays into B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. They present evidence for the decay B{sup 0} {yields} D{sub s}{sup -} K*{sup +} and the vector-vector decays B{sup 0} {yields} D{sub s}{sup *+} {rho}{sup -} and B{sup 0} {yields} D{sub s}{sup *-} K{sup *+}, as well as the first measurement of the vector meson polarization in these decays. They also determine the ratios of the CM-suppressed to CKM-favored amplitudes r(D{sup (*)}{pi}) and r(D{sup (*)}{rho}) in decays B{sup 0} {yields} D{sup (*)}{sup {+-}}{pi}{sup {-+}} and B{sup 0} {yields} D{sup (*)}{sup {+-}}{rho}{sup {-+}}, and comment on the prospects for measuring the Cp observable sin(2{beta} + {gamma}).
Date: April 16, 2008
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department

Study of B Meson Decays with Excited eta and eta-prime Mesons

Description: Using 383 million B{bar B} pairs from the BABAR data sample, they report results for branching fractions of six charged B-meson decay modes, where a charged kaon recoils against a charmless resonance decaying to K{bar K}* or {eta}{pi}{pi} final states with mass in the range (1.2-1.8) GeV/c{sup 2}. They observe a significant enhancement at the low K{bar K}* invariant mass which is interpreted as B{sup +} {yields} {eta}(1475)K{sup +}, find evidence for the decay B{sup +} {yields} {eta}(1295)K{sup +}, and place upper limits on the decays B{sup +} {yields} {eta}(1405)K{sup +}, B{sup +} {yields} f{sub 1}(1285)K{sup +}, B{sup +} {yields} f{sub 1}(1420)K{sup +}, and B{sup +} {yields} {phi}(1680)K{sup +}.
Date: April 18, 2008
Creator: Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J. P.; Poireau, V. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Hadronic Form factor in D0 to K- e+ nu_e Decays

Description: The shape of the hadronic form factor f{sub +} (q{sup 2}) in the decay D{sup 0} {yields} K{sup -} e{sup +}{nu}{sub e} has been measured in a model independent analysis and compared with theoretical calculations. They use 75 fb{sup -1} of data recorded by the BABAR detector at the PEPII electron-positron collider. The corresponding decay branching fraction, relative to the decay D{sup 0} {yields} K{sup -} {pi}{sup +}, has also been measured to be R{sub D} = BR(D{sup 0} {yields} K{sup -}e{sup +}{nu}{sub e})/BR(D{sup 0} {yields} K{sup -}{pi}{sup +}) = 0.927 {+-} 0.007 {+-} 0.012. From these results, and using the present world average value for BR(D{sup 0} {yields} K{sup -}{pi}{sup +}), the normalization of the form factor at q{sup 2} = 0 is determined to be f{sub +}(0) = 0.727 {+-} 0.007 {+-} 0.005 {+-} 0.007 where the uncertainties are statistical, systematic, and from external inputs, respectively.
Date: April 9, 2007
Creator: Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J. P.; Poireau, V. et al.
Partner: UNT Libraries Government Documents Department

The e+e- to to K+ K- \pi+\pi-, K+ K- \pi0\pi0 and K+ K- K+ K- Cross Sections Measured with Initial-State Radiation

Description: We study the processes e{sup +}e{sup -} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{gamma}, K{sup +}K{sup -}{pi}{sup 0}{pi}{sup 0}{gamma} and K{sup +}K{sup -}K{sup +}K{sup -}{gamma}, where the photon is radiated from the initial state. About 34600, 4400 and 2300 fully reconstructed events respectively, are selected from 232 fb{sup -1} of BABAR data. The invariant mass of the hadronic final state defines the effective e{sup +}e{sup -} center-of-mass energy, so that the K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{gamma} data can be compared with direct measurements of the e{sup +}e{sup -} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{gamma} reaction; no direct measurements exist for the e{sub +}e{sub -} {yields} K{sup +}K{sup -}{pi}{sup 0}{pi}{sup 0}{gamma} or e{sub +}e{sub -} {yields} K{sup +}K{sup -}K{sup +}K{sup -} reactions. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from e{sup +}e{sup -} {yields} {phi}(1020)f{sub 0}(980) and study its structure near threshold. In the charmonium region, we observe the J/{psi} in all three final states and several intermediate states, as well as the {psi}/(2S) in some modes, and measure the corresponding branching fractions. We see no signal for the Y(4260) and obtain an upper limit of {Beta}{sub Y(4260){yields}{phi}{pi}{sup +}{pi}{sup -}} {center_dot} {Lambda}{sub ee}{sup Y} < 0.4 eV at 90% C.L.
Date: May 4, 2007
Creator: Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J. P.; Poireau, V. et al.
Partner: UNT Libraries Government Documents Department

Observation of a Broad Structure at an Invariant Massof 4.32 GeV in the Reaction e+e- to pi+pi-psi(2S) Measured at BaBar

Description: The authors measure the cross section for the process e{sup +}e{sup -} {yields} {pi}{sup +}{pi}{sup -}{psi}(2S) from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the PEP-II e{sup +}e{sup -} storage rings. The study is based on 298 fb{sup -1} of data recorded with the BABAR detector. A structure is observed in the cross-section not far above threshold, near 4.32 GeV. This structure is not compatible with the Y(4260) previously reported by this experiment. A single resonance is adequate to describe the cross-section in the low-energy region (< 5.7 GeV).
Date: October 31, 2006
Creator: Aubert, B.; Barate, R.; Bona, M.; Boutigny, D.; Couderc, F.; Karyotakis, Y. et al.
Partner: UNT Libraries Government Documents Department