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## Main Question or Discussion Point

http://arxiv.org/PS_cache/hep-ph/pdf/0601/0601236.pdf [Broken]

Anyone seen this?:-

You'll probablly have to read the PDF to get a good view as the layout get's a bit mangled by the forum.

Here's the source paper, sounds interesting if a little speculative? Thoughts?Praise? condemnation, sneering indignation?

Anyone seen this?:-

You'll probablly have to read the PDF to get a good view as the layout get's a bit mangled by the forum.

Here's the source paper, sounds interesting if a little speculative? Thoughts?Praise? condemnation, sneering indignation?

edited for length - please only post a brief portion of the article and allow people to download themselves. Thanks.arXiv:hep-ph/0601236 v1 27 Jan 2006

Very Special Relativity

Andrew G. Cohen and Sheldon L. Glashow†

Physics Department, Boston University

Boston, MA 02215, USA

(Dated: Jan 26, 2006)

By Very Special Relativity (VSR) we mean descriptions of nature whose space-time symmetries

are certain proper subgroups of the Poincar´e group. These subgroups contain space-time translations

together with at least a 2-parameter subgroup of the Lorentz group isomorphic to that generated

by Kx + Jy and Ky − Jx. We find that VSR implies special relativity (SR) in the context of local

quantum field theory or of CP conservation. Absent both of these added hypotheses, VSR provides

a simulacrum of SR for which most of the consequences of Lorentz invariance remain wholly or

essentially intact, and for which many sensitive searches for departures from Lorentz invariance

must fail. Several feasible experiments are discussed for which Lorentz-violating eects in VSR may

be detectable.

Special relativity (SR) is based on the hypothesis that

the laws of physics share many of the symmetries of

Maxwell’s equations. Whereas the maximal symmetry

group of Maxwell’s equations is the 15-parameter confor-

mal group SU(2, 4), the existence of particles with mass

(and the known violations of P and T ) constrains space-

time symmetry to be no greater than the Poincar´e group

(the connected component of the Lorentz group along

with space-time translations). The special theory of rel-

ativity identifies this group as the symmetry of nature.

Although no decisive departure from exact Lorentz

invariance has yet been detected, ever more sensitive

searches should be and are being carried out. A per-

turbative framework has been developed to investigate a

certain class of departures from Lorentz invariance. For

example, Coleman and Glashow[1, 2] consider the case of

space-time translations along with exact rotational sym-

metry in the rest frame of the cosmic background radia-

tion, but allow small departures from boost invariance

in this frame. Perturbative departures from Lorentz-

invariance are then readily parametrized in terms of a

fixed time-like 4-vector or ‘spurion.’ Others[3, 4] consider

the introduction into the Lagrangian of more general

spurion-mediated perturbations (sometimes referred to

as ‘expectation values of Lorentz tensors following spon-

taneous Lorentz breaking.’)

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