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891.
W. Urban T. Rzaca-Urban N. Schulz J.L. Durell W.R. Phillips A.G. Smith B.J. Varley I. Ahmad 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):303-307
Excited levels in 140Xe and 142Xe nuclei, populated in the spontaneous fission of 248Cm, were studied by means of prompt γ-ray spectroscopy, using EUROGAM2 array. We report the first observation of an octupole
band in 142Xe and extend the octupole band in 140Xe. Level schemes of 140Xe and 142Xe obtained in this work show patterns characteristic of ocupole-vibrational bands. Properties of octupole bands in Xe isotopes
indicate that octupole correlations in these nuclei are lower than in the corresponding Ba nuclei. The electric dipole moment
of 142Xe was found to be larger than in other Xe isotopes, contrary to theoretical predictions. This may be due to the special role
of the N = 88 neutron number.
Received: 18 November 2002 / Accepted: 15 December 2002 / Published online: 25 February 2003
RID="a"
ID="a"e-mail: urban@fuw.edu.pl
Communicated by D. Schwalm 相似文献
892.
It is shown that the natural action of the absolute Galois groupon the ideals defining principal congruence subgroups of certainnonarithmetic Fuchsian triangle groups is compatible with itsaction on the algebraic curves that these congruence groupsuniformize. 相似文献
893.
Eisenstein BI Ernst J Gladding GE Gollin GD Hans RM Johnson E Karliner I Marsh MA Plager C Sedlack C Selen M Thaler JJ Williams J Edwards KW Sadoff AJ Ammar R Bean A Besson D Zhao X Anderson S Frolov VV Kubota Y Lee SJ Poling R Smith A Stepaniak CJ Urheim J Ahmed S Alam MS Athar SB Jian L Ling L Saleem M Timm S Wappler F Anastassov A Eckhart E Gan KK Gwon C Hart T Honscheid K Hufnagel D Kagan H Kass R Pedlar TK Thayer JB von Toerne E Zoeller MM Richichi SJ Severini H Skubic P Undrus A Savinov V 《Physical review letters》2001,87(6):061801
Using 12.7 fb(-1) of data collected with the CLEO detector at CESR, we observed two-photon production of the cc states chi(c0) and chi(c2) in their decay to pi(+)pi(-)pi(+)pi(-). We measured gamma(gammagamma)(chi(c))xB(chi(c)-->pi(+)pi(-)pi(+)pi(-)) to be 75+/-13(stat)+/-8(syst) eV for the chi(c0) and 6.4+/-1.8(stat)+/-0.8(syst) eV for the chi(c2), implying gamma(gammagamma)(chi(c0)) = 3.76+/-0.65(stat)+/-0.41(syst)+/-1.69(br) keV and gamma(gammagamma)(chi(c2)) = 0.53+/-0.15(stat)+/-0.06(syst)+/-0.22(br) keV. Also, cancellation of dominant experimental and theoretical uncertainties permits a precise comparison of gamma(gammagamma)(chi(c0))/gamma(gammagamma)(chi(c2)), evaluated to be 7.4+/-2.4(stat)+/-0.5(syst)+/-0.9(br), with QCD-based predictions. 相似文献
894.
Südmeyer T Aus der Au J Paschotta R Keller U Smith PG Ross GW Hanna DC 《Optics letters》2001,26(5):304-306
We demonstrate what is to our knowledge the first synchronously pumped high-gain optical parametric oscillator (OPO) with feedback through a single-mode fiber. This device generates 2.3-2.7 W of signal power in 700-900-fs pulses tunable in a wavelength range from 1429 to 1473 nm. The necessary high gain was obtained from a periodically poled LiTaO(3) crystal pumped with as much as 8.2 W of power at 1030 nm from a passively mode-locked Yb:YAG laser with 600-fs pulse duration and a 35-MHz repetition rate. The fiber-feedback OPO setup is compact because most of the resonator feedback path consists of a standard telecom fiber. Because of the high parametric gain, the fiber-feedback OPO is highly insensitive to intracavity losses. For the same reason, the synchronization of the cavity with the pump laser is not critical, so active stabilization of the cavity length is not required. 相似文献
895.
Yang UK Adams T Alton A Arroyo CG Avvakumov S de Barbaro L de Barbaro P Bazarko AO Bernstein RH Bodek A Bolton T Brau J Buchholz D Budd H Bugel L Conrad J Drucker RB Fleming BT Formaggio JA Frey R Goldman J Goncharov M Harris DA Johnson RA Kim JH King BJ Kinnel T Koutsoliotas S Lamm MJ Marsh W Mason D McFarland KS McNulty C Mishra SR Naples D Nienaber P Romosan A Sakumoto WK Schellman H Sciulli FJ Seligman WG Shaevitz MH Smith WH Spentzouris P Stern EG Suwonjandee N Vaitaitis A Vakili M Yu J 《Physical review letters》2001,86(13):2742-2745
We report on the extraction of the structure functions F2 and DeltaxF(3) = xF(nu)(3)-xF(nu;)(3) from CCFR nu(mu)-Fe and nu;(mu)-Fe differential cross sections. The extraction is performed in a physics model-independent (PMI) way. This first measurement of DeltaxF(3), which is useful in testing models of heavy charm production, is higher than current theoretical predictions. The ratio of the F2 (PMI) values measured in nu(mu) and mu scattering is in agreement (within 5%) with the predictions of next-to-leading-order parton distribution functions using massive charm production schemes, thus resolving the long-standing discrepancy between the two sets of data. 相似文献
896.
Ammar R Bean A Besson D Davis R Kwak N Zhao X Anderson S Frolov VV Kubota Y Lee SJ Mahapatra R O'Neill JJ Poling R Riehle T Smith A Stepaniak CJ Urheim J Ahmed S Alam MS Athar SB Jian L Ling L Saleem M Timm S Wappler F Anastassov A Duboscq JE Eckhart E Gan KK Gwon C Hart T Honscheid K Hufnagel D Kagan H Kass R Pedlar TK Schwarthoff H Thayer JB von Toerne E Zoeller MM Richichi SJ Severini H Skubic P Undrus A Chen S Fast J Hinson JW Lee J Miller DH Shibata EI Shipsey IP Pavlunin V 《Physical review letters》2001,86(7):1167-1170
Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the Sigma(*+)(c) charmed baryon, and an updated measurement of the mass of the Sigma(+)(c) baryon. We find M(Sigma(*+)(c))-M(Lambda(+)(c)) = (231.0+/-1.1+/-2.0) MeV, and M(Sigma(+)(c))-M(Lambda(+)(c)) = (166.4+/-0.2+/-0.3) MeV, where the errors are statistical and systematic, respectively. 相似文献
897.
Larry Smith 《Proceedings of the American Mathematical Society》2000,128(8):2199-2201
Let be a finite group and a complex representation. Barbara Schmid has shown that the algebra of invariant polynomial functions on the vector space is generated by homogeneous polynomials of degree at most , where is the largest degree of a generator in a minimal generating set for , and is the complex regular representation of . In this note we give a new proof of this result, and at the same time extend it to fields whose characteristic is larger than , the order of the group .
898.
An extensive physiological literature, including experimental and clinical studies in humans, demonstrates that activation of the medial olivocochlear (MOC) efferent system, by either contralateral sound or electrical stimulation, can produce significant alterations in cochlear function and suggests a role for the MOC system in influencing the auditory behavior of binaural hearing. The present data are from psychophysical studies in nonhuman primates which seek to determine if the noted physiological changes in response to contralateral acoustic stimulation have a perceptual counterpart. Four juvenile Japanese macaques were trained to respond to the presence of 1-s sinusoids, presented to the test ear, in an operant reinforcement paradigm. Thresholds were compared for frequencies ranging from 1.0 to 4.0 kHz in quiet, with thresholds measured when continuous, two octave-band noise, centered on the test tone frequency, was presented in the contralateral ear. Contralateral noise was presented at levels of 10-60 dB above detection threshold for the test-tone frequency. While some variability was evident across subjects, both in the frequency distribution and magnitude (as a function of contralateral noise level), all subjects exhibited an increase, or suppression of thresholds in the presence of contralateral noise. On average, thresholds increased systematically with contralateral noise level, to a peak of 7 dB. In one subject, the threshold increase seen with contralateral noise was significantly reduced when the MOC was surgically sectioned on the floor of the IVth ventricle. The characteristics of the measured shifts in behavioral thresholds, in the presence of contralateral noise reported here, are qualitatively and quantitatively similar to both efferent physiological suppression effects and psychophysical central masking threshold shifts which have been reported previously. These data suggest that at least some aspects of "central masking" are efferent-mediated peripheral processes, and that the term "central masking" may be incorrect. 相似文献
899.
Duxbury G McPhail MJ Smith KM Nivellini G Tullini F Celli A 《Journal of Molecular Spectroscopy》2000,199(1):13-17
High-resolution FTIR spectra of 1,1,1-trifluoroethane (HFC-143a) have been recorded in the region from 1370 to 1470 cm(-1) with an unapodized resolution of 0.0016 cm(-1) at room temperature and of 0.004 cm(-1) at 183 and 100 K. The two main infrared active bands of A(1) symmetry have been shown to be nu(2) at 1407.5 cm(-1) and nu(4) + nu(5) at 1440.5 cm(-1). With the aid of Raman spectra, the two infrared inactive bands of E symmetry in this spectra region have been shown to be nu(8) at 1457.5 cm(-1) and nu(6) + nu(9) at 1446.2 cm(-1). The nu(2) band was analyzed as an isolated band, whereas the nu(4) + nu(5) band was analyzed as part of the triad nu(4) + nu(5), nu(6) + nu(9), and nu(8). Copyright 2000 Academic Press. 相似文献
900.
We have determined the relative stability of stoichiometric, oxygen-rich, and aluminum-rich Al/Al 2O (3) and Ag/Al 2O (3) interfaces from first principles. Stable structures vary significantly with oxygen chemical potentials. Computed works of adhesion agree reasonably well with sessile drop experimental values, including correlation with measured oxygen chemisorption effects on Ag. The ordering of predicted bond energies of the interfaces, ceramics, and metals seems consistent with monotonic and fatigue fracture experiments. 相似文献