The Reverend Doctor Bob's Home Page
Bob McElrath
PH-TH Division
CERN
Geneva 23
CH-1211, Switzerland
office (53-1-029) phone: +41 22 76 78832
email: my first name @ my last name . org
Google Talk, Jabber, AIM, MSN, iChat, Yahoo Messenger, IRC: bsm117532
Skype: mcelrath
I am a Fellow in the Theory Division of CERN.
Previously I was a Post-Doctoral Researcher (aka PGR) at the University of California, Davis Physics Department. I am an avid
user and contributor to open-source software especially Linux and the Debian Project.
The SPIRES
database is the best place to find an up-to-date list of my
professional publications. I maintain mcelrath.org and mcelrath.net for my own use
and the use of members of my family (and any other poor sod with the last
name "McElrath"). I am an avid space nut and hope to someday get my butt
on Mars.
Other pages of interest:
Research Interests
I believe that first and foremost, physics exists because of experiment.
Theory is only useful so long as it can explain or predict phenomena. As such,
all my work has been, and will continue to be directly related to experiments
that can be performed in the near future. Any way I can assist
experimentalists is in my mind the most important contribution I can make. For
example, I have been actively communicating with experimentalists at BaBar
regarding my recent light dark matter and Higgs papers, and experimentalists at
CMS and CDF regarding Higgs searches. I have extensive experience with
high-energy experiments, having worked on D0 (under Heidi Schellman), ALEPH,
and BaBar (under Sau Lan Wu) early in my career. This makes me an effective
go-between for theory and experiment, and I will use this to my advantage in
the LHC era.
Dark Matter
We are also on the cusp of solving the Dark Matter problem. If our current
biases are correct, the LHC will be a Dark Matter "Factory". Determining the
properties of any new Dark Matter particle is of the utmost importance. Thus I
have proposed several new ways to reconstrut the mass of missing particles, and
other particles that may be produced in conjunction with them (as occurs in the
most popular models, such as Supersymmetry). However the LHC is and LEP was
best suited to producing Dark Matter that is associated with a new charged or
colored particle (such as squarks and sleptons). As a consequence, almost all
Dark Matter limits are actually limits arising from these new charged/colored
objects, within the framework of very specific model assumptions, not limits on
the Dark Matter itself. The lowest Dark Matter mass that would be acceptable
is 1011 times lighter than our current biases of around 100 GeV.
Thus in recent papers I have suggested innovative new and overlooked
measurements that cover ignored parts of the parameter space in a collider
setting, that can be done at existing B, tau, and charm-factories. Several of
these measurements have now been made at BES, CLEO, and Belle. (Unfortunately,
no discoveries yet...)
Higgs and electroweak symmetry breaking
The planned startup date of the LHC is in 2008. As the highest energy collider
operating, it will have a window into the mechanism of electroweak symmetry
breaking and mass. It is of the utmost importance that we are prepared to find
whatever the LHC presents to us. I will continue to pursue detailed collider
studies that can reveal the nature of electroweak symmetry breaking and the
origin of mass. I am actively participating in the CP-Violating and
Non-Standard Higgs (CPNSH) working group, to help chart the landscape of things
that might be seen at the LHC. An important upcoming contribution in this area
is Higgs-to-Higgs decays, which have been largely overlooked by existing
studies, and will require clever techniques to discover. These decays exist in
almost every extended model, and should be pursued both theoretically and
experimentally. Most recently I have pursued the largely-ignored parameter
space for light higgses. If a Higgs scalar is decoupled from the Z, there are
few direct limits on its mass. CLEO has recently performed such a search,
improving the limits on light higgses by about an order of magnitude.
Hierarchy Problems
It is currently in vogue to ignore hierarchies such as the electroweak and
cosmological hierarchy problems, mostly for pragmatic reasons. However, these
really represent a serious inconsistency within our own theories, and at the
end of the day, any theory that predicts these kinds of problems is wrong.
Quantum Field Theory and String Theory have both been spectacular failures at
explaining the apparent discrepancy between the Planck scale and the
electroweak scale. What's worse is that if the solution does lie in high
energy phenomena (e.g. String Theory), we might never discover it. I
believe that the answer does not lie in the high energy theory at all, and
solutions should be sought in low-energy dynamics. A possible solution is that
field theory is renormalizable to arbitrarily high energies (e.g. gravity does
not provide a cutoff to field theory), and gravity arises as an effective
theory.
Non-Physics
I'm interested in all ways of using computers to augment my abilities. The
current incarnation of this theme in my life is TiddlyWiki, a personal browser-based wiki,
in which I keep notes and ideas. However being a physicist, there's no way to
jot down ideas without a few equations, so I've written a plugin which interfaces the excellent jsMath javascript-based
TeX rendering system with TiddlyWiki.
When I'm not doing geeky things I also like to run, hike, bike, backpack,
kayak, snowboard, and generally be outdoors.