It has been known that Little Higgs models with T-parity, which can give a dark matter candidate, suffer from the anomalies of given models through the Wess-Zumino-Witten term, which in turn can violate the T-parity. Here we thus introduce a new kind of discrete symmetry called Z-parity, which is a residual gauge symmetry of an additional U (1) symmetry of the extended gauge group of the Little Higgs models. Because Z-parity comes from the gauge symmetry, this discrete symmetry not only remains unbroken under the anomalies but also can give the lightest Z-parity particle, which is stable and becomes a viable dark matter candidate. We also show that there is an allowed parameter space in the global symmetry breaking scale f versus the mass of the dark matter, which satisfies the current relic density of the cold dark matter.
|Number of pages||6|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Publication status||Published - 2010 May 10|
Bibliographical noteFunding Information:
C.S.K. was supported in part by Basic Science Research Program through the NRF of Korea funded by MOEST ( 2009-0088395 ) and in part by KOSEF through the Joint Research Program ( F01-2009-000-10031-0 ). J.B.P. thanks S.K. Kang for valuable discussions and encouragement about this Letter and H.S. Lee for his kind and critical opinions.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics