51 research outputs found
Geometric Transition versus Cascading Solution
We study Vafa's geometric transition and Klebanov - Strassler solution from
various points of view in M-theory. In terms of brane configurations, we show
the detailed equivalences between the two models. In some limits, both models
have an alternative realization as fourfolds in M-theory with appropriate
G-fluxes turned on. We discuss some aspects of the fourfolds including how to
see the transition and a possible extension to the non-supersymmetric case.Comment: 34 pages, LaTex, 2 figures; v2: Some comments added and references
updated. Final version to appear in JHE
The Volume of some Non-spherical Horizons and the AdS/CFT Correspondence
We calculate the volumes of a large class of Einstein manifolds, namely
Sasaki-Einstein manifolds which are the bases of Ricci-flat affine cones
described by polynomial embedding relations in C^n. These volumes are important
because they allow us to extend and test the AdS/CFT correspondence. We use
these volumes to extend the central charge calculation of Gubser (1998) to the
generalized conifolds of Gubser, Shatashvili, and Nekrasov (1999). These
volumes also allow one to quantize precisely the D-brane flux of the AdS
supergravity solution. We end by demonstrating a relationship between the
volumes of these Einstein spaces and the number of holomorphic polynomials
(which correspond to chiral primary operators in the field theory dual) on the
corresponding affine cone.Comment: 25 pp, LaTeX, 1 figure, v2: refs adde
The differential effects of concurrent planning practice elements on reunification and adoption
Objective: The child welfare practice of concurrent planning attempts to shorten children\u27s stays in foster care. There is very little quantitative research on concurrent planning\u27s effects. This study examines the influence of concurrent planning practice elements (reunification prognosis, concurrent plan, full disclosure, and discussion of voluntary relinquishment) on reunification and adoption. Method: Using a sample of 885 children, an observational design, and statistical controls, children who received concurrent planning elements were compared to those who did not. Results: Findings show discussion of voluntary relinquishment to be positively associated with adoption and full disclosure to be negatively associated with reunification. Conclusions: Concurrent planning\u27s benefits may require more intensive services to be fully realized. Care should be taken to ensure activities achieve their intended effects
Measurement of the Ds lifetime
We report precise measurement of the Ds meson lifetime. The data were taken
by the SELEX experiment (E781) spectrometer using 600 GeV/c Sigma-, pi- and p
beams. The measurement has been done using 918 reconstructed Ds. The lifetime
of the Ds is measured to be 472.5 +- 17.2 +- 6.6 fs, using K*(892)0K+- and phi
pi+- decay modes. The lifetime ratio of Ds to D0 is 1.145+-0.049.Comment: 5 pages, 2 figures submitted to Phys. Lett.
Confirmation of the Double Charm Baryon Xi_cc+ via its Decay to p D+ K-
We observes a signal for the double charm baryon Xi_cc+ in the charged decay
mode Xi_cc+ -> p D+ K- to complement the previously reported decay Xi_cc+ ->
Lambda_c K- pi+ in data from SELEX, the charm hadro-production experiment
(E781) at Fermilab. In this new decay mode we observe an excess of 5.62 events
over an expected background estimated by event mixing to be 1.38+/-0.13 events.
The Poisson probability that a background fluctuation can produce the apparent
signal is less than 6.4E-4. The observed mass of this state is
(3518+/-3)MeV/c^2, consistent with the published result. Averaging the two
results gives a mass of (3518.7+/-1.7)MeV/c^2. The observation of this new weak
decay mode confirms the previous SELEX suggestion that this state is a double
charm baryon. The relative branching ratio Gamma(Xi_cc+ -> pD+K-)/Gamma(Xi_cc+
-> Lambda_c K- pi+) = 0.36+/-0.21.Comment: 11 pages, 6 included eps figures. v2 includes improved statistical
method to determine significance of observation. Submitted to PL
Hadronic Production of Lambda_c from 600 GeV/c pion, sigma and proton beams
We present data from Fermilab experiment E781 (SELEX) on the hadroproduction
asymmetry for anti-Lambda_c compared to Lambda_c+ as a function of xF and pt2
distributions for Lambda_c+. These data were measured in the same apparatus
using incident pi-, sigma- beams at 600 GeV/c and proton beam at 540 GeV/c. The
asymmetry is studied as a function of xF. In the forward hemisphere with xF >=
0.2 both baryon beams exhibit very strong preference for producing charm
baryons rather than charm antibaryons, while the pion beam asymmetry is much
smaller. In this energy regime the results show that beam fragments play a
major role in the kinematics of Lambda_c formation, as suggested by the leading
quark picture.Comment: 6 pages, 5 figures (postscript), RevTeX, submitted to Phy. Rev. Let
First Observation of the Cabibbo-suppressed Decays Xi_c+ -> Sigma+ pi- pi+ and Xi_c+ -> Sigma- pi+ pi+ and Measurement of their Branching Ratios
We report the first observation of two Cabibbo-suppressed decay modes, Xi_c+
-> Sigma+ pi- pi+ and Xi_c+ -> Sigma- pi+ pi+. We observe 59+/-14 over a
background of 87, and 22+/-8 over a background of 13 events, respectively, for
the signals. The data were accumulated using the SELEX spectrometer during the
1996-1997 fixed target run at Fermilab, chiefly from a 600GeV/c Sigma- beam.
The branching ratios of the decays relative to the Cabibbo--favored Xi_c+ ->
Xi- pi+ pi+ are measured to be B(Xi_c+ -> Sigma+ pi- pi+)/B(Xi_c+ -> Xi- pi+
pi+) = 0.48+/-0.20, and B(Xi_c+ -> Sigma- pi+ pi+)/B(Xi_c+ -> Xi- pi+ pi+) =
0.18+/-0.09, respectively. We also report branching ratios for the same decay
modes of the Lambda_c+ relative to Lambda_c+ -> p K- pi+.Comment: 15 pages, 5 figures, version 2 as accepted in PL
Total Cross Section Measurements With π- , Σ- And Protons On Nuclei And Nucleons Around 600 Gev/c
Total cross sections for Σ- and π- on beryllium, carbon, polyethylene and copper as well as total cross sections for protons on beryllium and carbon have been measured in a broad momentum range around 600GeV/c . These measurements were performed with a transmission technique in the SELEX hyperon-beam experiment at Fermilab. We report on results obtained for hadron-nucleus cross sections and on results for σtot(Σ-N) and σtot(π-N) , which were deduced from nuclear cross sections. © 2000 Elsevier Science B.V.57901/02/15277312Langland, J.L., (1995) Ph.D. Thesis, , University of IowaKleinfelder, S.A., (1988) IEEE Trans. Nucl. Sci., 35 (1)Dersch, U., (1998) Ph.D. Thesis, HeidelbergBiagi, S.F., (1981) Nucl. Phys. B, 186, pp. 1-21Bellettini, G., (1966) Nucl. Phys., 79, pp. 609-624Schiz, A.M., (1980) Phys. Rev. D, 21, pp. 3010-3022Murthy, P.V.R., (1975) Nucl. Phys. B, 92, pp. 269-308Caso, C., (1998) Eur. Phys. J. C, 3. , http://pdg.lbl.gov/1998/contents_plots.html, and data on total cross sections from computer readable filesSchiz, A.M., (1979) Ph.D. Thesis, , Yale University(1973) Landolt Börnstein Tables, 7. , Springer editionEngler, J., (1970) Phys. Lett. B, 32, pp. 716-719Babaev, A., (1974) Phys. Lett. B, 51, pp. 501-504Glauber, R.J., (1959) Boulder Lectures, pp. 315-413Franco, V., (1972) Phys. Rev. C, 6, pp. 748-757Karmanov, V.A., Kondratyuk, L.A., (1973) JETP Lett., 18, pp. 266-268Burq, J.P., (1983) Nucl. Phys. B, 217, pp. 285-335Gross, D., (1978) Phys. Rev. Lett., 41, pp. 217-220Beznogikh, G.G., (1972) Phys. Lett. B, 39, pp. 411-413Vorobyov, A.A., (1972) Phys. Lett. B, 41, pp. 639-641Foley, K.J., (1967) Phys. Rev. Lett., 19, pp. 857-859Fajardo, L.A., (1981) Phys. Rev. D, 24, pp. 46-65Jenni, P., (1977) Nucl. Phys. B, 129, pp. 232-252Breedon, R.E., (1989) Phys. Rev. Lett. B, 216, pp. 459-465Amos, N., (1983) Phys. Rev. Lett. B, 128, pp. 343-348Amaldi, U., (1977) Phys. Rev. Lett. B, 66, pp. 390-394Amos, N., (1985) Nucl. Phys. B, 262, pp. 689-714Akopin, V.D., (1977) Sov. J. Nucl. Phys., 25, pp. 51-55Amirkhanov, I.V., (1973) Sov. J. Nucl. Phys., 17, pp. 636-637Foley, K.J., (1969) Phys. Rev., 181, pp. 1775-1793Apokin, V.D., (1976) Nucl. Phys. B, 106, pp. 413-429Burq, J.P., (1982) Phys. Lett. B, 109, pp. 124-127Dakhno, L.G., (1983) Sov. J. Nucl. Phys., 37, pp. 590-598Kazarinov, M., (1976) Sov. Phys. JETP, 43, pp. 598-606De Jager, C.W., (1974) At. Data Nucl. Data Tables, 14, pp. 479-508Donnachie, A., Landshoff, P.V., (1992) Phys. Lett. B, 296, pp. 227-232Lipkin, H., (1975) Phys. Rev. D, 11, pp. 1827-1831Barnett, R.M., (1996) Phys. Rev. D, 54, pp. 191-192Carroll, A.S., (1979) Phys. Lett. B, 80, pp. 423-427Badier, J., (1972) Phys. Lett. B, 41, pp. 387-39
Total Cross Section Measurements with pi-, Sigma- and Protons on Nuclei and Nucleons around 600 GeV/c
Total cross sections for Sigma- and pi- on beryllium, carbon, polyethylene
and copper as well as total cross sections for protons on beryllium and carbon
have been measured in a broad momentum range around 600GeV/c. These
measurements were performed with a transmission technique adapted to the SELEX
hyperon-beam experiment at Fermilab. We report on results obtained for
hadron-nucleus cross sections and on results for sigma_tot(Sigma- N) and
sigma_tot(pi- N), which were deduced from nuclear cross sections.Comment: 42 pages, submitted to Nucl.Phys.
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