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排序方式: 共有287条查询结果,搜索用时 140 毫秒
71.
We re-examine the question of radiative symmetry breaking in the Standard Model in the presence of right-chiral neutrinos and a minimally enlarged scalar sector. We demonstrate that, with these extra ingredients, the hypothesis of classically unbroken conformal symmetry, besides naturally introducing and stabilizing a hierarchy, is compatible with all available data; in particular, there exists a set of parameters for which the model may remain viable even up to the Planck scale. The decay modes of the extra scalar field provide a unique signature of this model which can be tested at LHC. 相似文献
72.
Procedures are presented for the purification of the subunit dimer from Acanthochiton fasicularis hemocyanin. Electron microscopy of negatively stained specimens revealed a uniform population of macromolecules possessing the characteristic "boat shape". A 3D reconstruction from this EM data generated a approximately 3 nm resolution model that correlates well with earlier data of the purported subunit dimer, extracted from the 3D reconstruction of the didecamer of Haliotis tuberculata hemocyanin type 1. 相似文献
73.
McIlhany K McKeown RD Meissner F Menden FM Metz A Meyners N Mikloukho O Miller CA Miller MA Milner R Most A Muccifora V Naryshkin Y Nathan AM Neunreither F Niczyporuk M Nowak W O'Neill TG Openshaw R Ouyang J Owen BR Pate SF Potashov S Potterveld DH Rakness G Redwine R 《Physical review letters》2000,84(12):2584-2588
We present a measurement of the longitudinal spin asymmetry A(||) in photoproduction of pairs of hadrons with high transverse momentum p(T). Data were accumulated by the HERMES experiment using a 27.5 GeV polarized positron beam and a polarized hydrogen target internal to the HERA storage ring. For h(+)h(-) pairs with p(h(1))(T)>1.5 GeV/c and p(h(2))(T)>1.0 GeV/c, the measured asymmetry is A(||) = -0. 28+/-0.12(stat)+/-0.02(syst). This negative value is in contrast to the positive asymmetries typically measured in deep inelastic scattering from protons, and is interpreted to arise from a positive gluon polarization. 相似文献
74.
75.
76.
Yoshitake Yamazaki Henk J. Hilhorst Günther Meissner 《Journal of statistical physics》1980,23(5):609-625
With the aid of the differential real-space method we derive exact renormalization group (RG) equations for the Gaussian model ind dimensions. The equations involved + 1 spatially dependent nearest-neighbor interactions. We locate a critical fixed point and obtain the exact thermal critical indexy
T
= 2. A special trajectory of the full nonlinear RG transformation is found and the free energy of the corresponding initial state calculated.Supported by Deutsche Forschungsgemeinschaft through Sonderforschungsbereich 130 Ferroelektrika. 相似文献
77.
We consider a class of higher order corrections in the form of Euler densities of arbitrary rank n to the standard gravity action in D dimensions. We present a generating functional and an explicit form of the conserved energy-momentum tensors. We show that this class of corrections allows for domain-wall solutions despite the presence of higher powers of the curvature. The existence of such solutions no longer depends on the presence of cosmological constants. For example, the Randall-Sundrum-type scenario can be realized without bulk and/or brane cosmological constant. 相似文献
78.
Rüegg Ch Oettli M Schefer J Zaharko O Furrer A Tanaka H Krämer KW Güdel HU Vorderwisch P Habicht K Polinski T Meissner M 《Physical review letters》2004,93(3):037207
Elastic and inelastic neutron scattering experiments have been performed on the dimer spin system NH4CuCl3, which shows plateaus in the magnetization curve at m=1/4 and m=3/4 of the saturation value. Two structural phase transitions at T1 approximately 156 K and at T(2)=70 K lead to a doubling of the crystallographic unit cell along the b direction and as a consequence a segregation into different dimer subsystems. Long-range magnetic ordering is reported below T(N)=1.3 K. The magnetic field dependence of the excitation spectrum identifies successive quantum phase transitions of the dimer subsystems as the driving mechanism for the unconventional magnetization process in agreement with a recent theoretical model. 相似文献
79.
Epelbaum E Kamada H Nogga A Witala H Glöckle W Meissner UG 《Physical review letters》2001,86(21):4787-4790
Recently developed chiral nucleon-nucleon (NN) forces at next-to-leading order (NLO), that describe NN phase shifts up to about 100 MeV fairly well, have been applied to 3N and 4N systems. Faddeev-Yakubovsky equations have been solved rigorously. The resulting 3N and 4N binding energies are in the same range as found using standard NN potentials. In addition, low-energy 3N scattering observables are very well reproduced as for standard NN forces. The long-standing A(y) puzzle is absent at NLO. The cutoff dependence of the scattering observables is rather weak. 相似文献
80.
Leinemann Inga Nkwusi Godswill Chimezie Timmo Kristi Volobujeva Olga Danilson Mati Raudoja Jaan Kaljuvee Tiit Traksmaa Rainer Altosaar Mare Meissner Dieter 《Journal of Thermal Analysis and Calorimetry》2018,134(1):409-421
Journal of Thermal Analysis and Calorimetry - We investigated various possible chemical interactions between individual precursor compounds (ZnSe, SnSe, and CuSe) and CdI2 as a flux material used... 相似文献