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1.
The standard model on non-commutative space-time 总被引:1,自引:0,他引:1
X. Calmet B. Jurčo P. Schupp J. Wess M. Wohlgenannt 《The European Physical Journal C - Particles and Fields》2002,23(2):363-376
We consider the standard model on a non-commutative space and expand the action in the non-commutativity parameter . No new particles are introduced; the structure group is . We derive the leading order action. At zeroth order the action coincides with the ordinary standard model. At leading order
in we find new vertices which are absent in the standard model on commutative space-time. The most striking features are couplings
between quarks, gluons and electroweak bosons and many new vertices in the charged and neutral currents. We find that parity
is violated in non-commutative QCD. The Higgs mechanism can be applied. QED is not deformed in the minimal version of the
NCSM to the order considered.
Received: 29 November 2001 / Published online: 25 January 2002 相似文献
2.
The algebra dual to Woronowicz's deformation of the two-dimensional Euclidean group is constructed. The same algebra is obtained from SU
q
(2) via contraction on both the group and algebra levels. 相似文献
3.
Schupp PJ Charlton TS Taylor MW Kjelleberg S Steinberg PD 《Analytical and bioanalytical chemistry》2005,383(1):132-137
A challenge for understanding the role of bacterial cell–cell signalling in the environment is the detection of those signals,
which are often present in low (nmol L−1) concentrations. We describe here a simple purification method, solid-phase extraction (SPE), for increasing the sensitivity
of detection for one such group of signals, acyl homoserine lactones (AHLs), in environmental samples. Spiking of dried marine
sponge tissue (Stylinos sp.) with AHLs resulted in detection down to 0.01 ppm for 3-oxo-hexanoyl homoserine lactone (3-oxo C6-HSL) and 1 ppm for hexanoyl homoserine lactone (C6-HSL). Compared with liquid extraction methods use of SPE resulted in twofold and tenfold improvements in sensitivity, respectively. 相似文献
4.
B. Melić K. Passek-Kumerički J. Trampetić P. Schupp M. Wohlgenannt 《The European Physical Journal C - Particles and Fields》2005,42(4):499-504
This paper is a direct extension of our earlier work on electroweak currents and the Higgs sector in the standard model on non-commutative space-time, now with strong interactions included. Apart from the non-commutative corrections to standard model strong interactions, several new interactions appear. The most interesting ones are gluonic interactions with the electroweak sector. They are elaborated here in detail and the Feynman rules for interactions up to
are provided.Received: 18 March 2005, Revised: 13 May 2005, Published online: 19 July 2005 相似文献
5.
P. Schupp J. Trampetić G. Raffelt 《The European Physical Journal C - Particles and Fields》2004,36(3):405-410
In this work we propose a possible mechanism of left- and right-handed neutrino couplings to photons, which arises quite naturally in non-commutative field theory. We estimate the predicted additional energy-loss in stars induced by space-time non-commutativity. The usual requirement that any new energy-loss mechanism in globular stellar clusters should not excessively exceed the standard neutrino losses implies a scale of non-commutative gauge theory above the scale of weak interactions.Received: 2 April 2004, Published online: 14 July 2004 相似文献
6.
We have used 70 Ci 183Ta Mössbauer sources to measure the Debye--Waller factors of NaCl, KCl, and KBr single crystals for several of the (h00) and (nnn) Bragg reflections. We have found that the procedure used to analyze data by earlier workers leads to incorrect parameters in the Debye--Waller factor exponent, and we use a procedure that eliminates the need to introduce an empirical parameter to account for thermal expansion effects. We observe that both the cations and anions in NaCl and KBr have identical Debye--Waller factors in the [nnn] direction. We observe Q4 terms in NaCl and KCl, with some evidence for a Q4 term in KBr. The size of this contribution varies with the direction of momentum transfer and will be reported. We observe that the Debye temperature and the coefficient of the anharmonic Q2 term also vary with direction of momentum transfer. We believe this to be the first definitive evidence for a non-spherical thermal cloud in a cubic crystal; the ions have a larger amplitude of oscillation in the [h00] direction than in the [nnn] direction. This effect is temperature dependent and greater at lower temperatures. 相似文献
7.
8.
Let F
k
be a free group of rank k ≥ 2 with a fixed set of free generators. We associate to any homomorphism φ from F
k
to a group G with a left-invariant semi-norm a generic stretching factor, λ(φ), which is a noncommutative generalization of the translation number. We concentrate on the situation where φ: F
k
→ Aut(X) corresponds to a free action of F
k
on a simplicial tree X, in particular, where φ corresponds to the action of F
k
on its Cayley graph via an automorphism of F
k
. In this case we are able to obtain some detailed “arithmetic” information about the possible values of λ = λ(φ). We show that λ ≥ 1 and is a rational number with 2kλ ∈ ℤ[1/(2k − 1)] for every φ ∈ Aut(F
k
). We also prove that the set of all λ(φ), where φ varies over Aut(F
k
), has a gap between 1 and 1+(2k−3)/(2k
2−k), and the value 1 is attained only for “trivial” reasons. Furthermore, there is an algorithm which, when given φ, calculates λ(φ).
The second and the third author were supported by the NSF grant DMS#0404991 and the NSA grant DMA#H98230-04-1-0115. 相似文献
9.
We discuss our experiences with exceptionally intense Mössbauer sources (of order 100 Ci) and their use in making precision determinations of line shape parameters. We review our measurements of interference and recoilless fraction using conventional transmission geometry. Fitting simultaneous sets of data with known constraints greatly improves the efficiency of line-shape determination. Measurements of interference have been made using a two-absorber technique first introduced by Mössbauer and coworkers. Our results indicate that the method can be useful for determining interference, but that incorrect line shape parameters are obtained if powder samples are used which do not comply well with the assumption of thickness uniformity in the absorber. 相似文献
10.