Threshold criterion for wetting at the triple point

Grand canonical simulations are used to calculate adsorption isotherms of various classical gases on alkali metal and Mg surfaces. Ab initio adsorption potentials and Lennard-Jones gas-gas interactions are used. Depending on the system, the resulting behavior can be nonwetting for all temperatures studied, complete wetting, or (in the intermediate case) exhibit a wetting transition. An unusual variety of wetting transitions at the triple point is found in the case of a specific adsorption potential of intermediate strength. The general threshold for wetting near the triple point is found to be close to that predicted with a heuristic model of Cheng et al. This same conclusion was drawn in a recent experimental and simulation study of Ar on CO_2 by Mistura et al. These results imply that a dimensionless wetting parameter w is useful for predicting whether wetting behavior is present at and above the triple temperature. The nonwetting/wetting crossover value found here is w circa 3.3.Comment: 15 pages, 8 figure

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

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

Nuclear Dependence Of Charm Production

Using data taken by SELEX during the 1996-1997 fixed target run at Fermilab, we study the production of charmed hadrons on copper and carbon targets with ∑ -, p, π -, and π + beams. Parametrizing the dependence of the inclusive production cross section on the atomic number A as A α, we determine α for D +, D 0, D s +, D +(2010), Λ c +, and their respective anti-particles, as a function of their transverse momentum p t and scaled longitudinal momentum x F . Within our statistics there is no dependence of α on x F for any charm species for the interval 0.1<x F <1.0. The average value of α for charm production by pion beams is α meson=0.850±0.028. This is somewhat larger than the corresponding average α baryon=0.755±0.016 for charm production by baryon beams (∑ -, p). © 2009 Springer-Verlag/Società Italiana di Fisica.644637644Cobbaert, H., (1987) Phys. Lett. B, 191, p. 456. , 10.1016/0370-2693(87)90639-3 1987PhLB.191.456CCobbaert, H., (1988) Phys. Lett. B, 206, p. 546. , 10.1016/0370-2693(88)91627-9Cobbaert, H., (1988) Phys. Lett. B, 213, p. 395. , 10.1016/0370-2693(88)91783-2 1988PhLB.213.395CLeitch, M.J., (2000) Phys. Rev. Lett., 84, p. 3256. , 10.1103/PhysRevLett.84.3256 2000PhRvL.84.3256L arXiv:nucl-ex/9909007Alessandro, B., Alexa, C., Arnaldi, R., Atayan, M., Baglin, C., Baldit, A., Beole, S., Willis, N., Charmonium production and nuclear absorption in p-A interactions at 450 GeV (2004) European Physical Journal C, 33 (1), pp. 31-40. , DOI 10.1140/epjc/s2003-01539-yAbt, I., (2009) Eur. Phys. J. C, 60, p. 525. , 10.1140/epjc/s10052-009-0965-7 2009EPJC.60.525A arXiv:0812.0734 [hep-ex]Heller, K.J., (1977) Phys. Rev. D, 16, p. 2737. , 10.1103/PhysRevD.16.2737 1977PhRvD.16.2737HSkubic, P., (1978) Phys. Rev. D, 18, p. 3115. , 10.1103/PhysRevD.18.3115 1978PhRvD.18.3115SAleev, A.N., (1987) Sov. J. Nucl. Phys., 46, p. 657. , [Yad. Fiz. 46, 1127 (1987)]Vecko, M., (1989) Czech. J. Phys. B, 39, p. 297. , 10.1007/BF01597781 1989CzJPh.39.297VAdamovich, M., (1992) Phys. Lett. B, 284, p. 453. , 10.1016/0370-2693(92)90460-L 1992PhLB.284.453AAlves, G.A., (1993) Phys. Rev. Lett., 70, p. 722. , 10.1103/PhysRevLett.70.722 1993PhRvL.70.722AAlves, G.A., (1994) Phys. Rev. D, 49, p. 4317. , 10.1103/PhysRevD.49.R4317 1994PhRvD.49.4317ALeitch, M.J., (1994) Phys. Rev. Lett., 72, p. 2542. , 10.1103/PhysRevLett.72.2542 1994PhRvL.72.2542LAdamovich, M., (1997) Nucl. Phys. B, 495, p. 3. , 10.1016/S0550-3213(97)00223-X 1997NuPhB.495.3AApanasevich, L., (1997) Phys. Rev. D, 56, p. 1391. , 10.1103/PhysRevD.56.1391 1997PhRvD.56.1391A arXiv:hep-ex/9702014Abt, I., (2007) Eur. Phys. J. C, 52, p. 531. , 10.1140/epjc/s10052-007-0427-z 2007EPJC.52.531A arXiv:0708.1443 [hep-ex]Duffy, M.E., (1985) Phys. Rev. Lett., 55, p. 1816. , 10.1103/PhysRevLett.55.1816 1985PhRvL.55.1816DVogt, R., The A dependence of open charm and bottom production (2003) International Journal of Modern Physics E, 12 (2), pp. 211-269. , DOI 10.1142/S0218301303001272Lourenco, C., Wohri, H.K., Heavy-flavour hadro-production from fixed-target to collider energies (2006) Physics Reports, 433 (3), pp. 127-180. , DOI 10.1016/j.physrep.2006.05.005, PII S0370157306001815Frawley, A.D., Ullrich, T., Vogt, R., (2008) Phys. Rept., 462, p. 125. , 10.1016/j.physrep.2008.04.002 2008PhR.462.125F arXiv:0806.1013 [nucl-ex]Russ, J.S., (1998) Proceedings of the 29th International Conference on High Energy Physics II World Scientific Singapore, 1259. , A. Astbury (eds), et al. arXiv:hep-ex/9812031Russ, J.S., (1998) Proceedings of the 29th International Conference on High Energy Physics, 2, p. 1259. , ed. by A. Astbury, et al. (World Scientific, Singapore) arXiv:hep-ex/9812031Engelfried, J., (1999) Nucl. Instrum. Methods A, 431, p. 53. , 10.1016/S0168-9002(99)00043-1 1999NIMPA.431.53E arXiv:hep-ex/9811001Kushnirenko, A., Alkhazov, G., Atamantchouk, A.G., Balatz, M.Y., Bondar, N.F., Cooper, P.S., Dauwe, L.J., Vishnyakov, V.E., Precision measurements of the ∧c+ and D 0 lifetimes (2001) Physical Review Letters, 86 (23), pp. 5243-5246. , DOI 10.1103/PhysRevLett.86.5243Garcia, F.G., (2002) Phys. Lett. B, 528, p. 49. , 10.1016/S0370-2693(01)01484-8 2002PhLB.528.49S arXiv:hep-ex/0109017Kaya, M., (2003) Phys. Lett. B, 558, p. 34. , 10.1016/S0370-2693(03)00246-6 2003PhLB.558.34S arXiv:hep-ex/0302039Brodsky, S.J., Kopeliovich, B., Schmidt, I., Soffer, J., (2006) Phys. Rev. D, 73, p. 113005. , 2006PhRvD.73k3005B arXiv:hep-ph/0603238Adamovich, M.I., (2003) Eur. Phys. J. C, 26, p. 357. , 10.1140/epjc/s2002-01073-6 2003EPJC.26.357WA. Blanco-Covarrubias, et al. (SELEX Collaboration), in preparatio