GammeV and GammeV-CHASE Page: 1 of 6
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
GammeV and GammeV-CHASE
Fermilab, MS209, Batavia IL, USA
on behalf of the GammeV and GammeV-CHASE Collaborations
1 Goal of the experiments
Physics beyond the Standard Model might include Weakly Interacting Slim
Particles (WISPs) that address questions such as what is the nature of
dark matter or even shed insight into the underlying nature of dark energy.
WISPs are a general class of particles that include axions, axion-like par-
ticles, hidden sector photons, milli-charged particles, chameleons, etc. The
GammeV (Gamma to _milli-eV) experiment originated in 2007 in order to
test a positive anomalous axion-like particle interpretation of the PVLAS
experiment which was not evident in subsequent data . The experiment
was also motivated as it was realized that the milli-eV scale appears natu-
rally in a see-saw between the electroweak and Planck scales, neutrino mass
differences, the dark energy density, and the possible mass for certain dark
matter candidates. GammeV was first to exclude both a scalar and pseu-
doscalar axion-like particle interpretation of the anomalous PVLAS result
setting a limit of around 3.1 x 10-7 GeV-- on the coupling to photons for
low mass axion-like particles.
It has also been found that the parameter space of a variety of other
WISP candidates is both largely unexplored and is accessible by modest
experiments employing lasers and possibly accelerator magnets. GammeV
data has also been used to set limits on possible hidden sector photons .
Further work by the GammeV team has focused on a reconfiguration of
the apparatus to be sensitive to possible chameleon particles. Chameleons
are scalar (or pseudoscalar) particles that couple to the stress energy tensor
in a potential such that their properties depend on their environment. In
particular, a chameleon acquires an effective mass which increases with local
matter density, p. For a certain class of such potentials, the chameleon field
has properties that might explain dark energy . GammeV set the first
limits on the coupling of chameleons to photons. A dedicated follow-up
experiment, GammeV-CHASE, (CHameleon Afterglow SEarch), has also
been performed and sets limits on both photon and some model dependent
matter couplings as a function of an effective chameleon mass.
Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
Here’s what’s next.
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Wester, W. GammeV and GammeV-CHASE, report, November 1, 2011; Batavia, Illinois. (https://digital.library.unt.edu/ark:/67531/metadc836765/m1/1/: accessed April 22, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.