This week, particle and astro-particle physicists from all over the world have converged on Philadelphia for the 34th International Conference on High-Energy Physics, or ICHEP (pronounced “Eye-Chep”). I’ve seen many friends and colleagues, and gotten a lot of exercise running from building to building to see the overlapping talks. There is a thick air of anticipation over the startup of the LHC, which is becoming imminent. However, there has also been a very exciting back-and-forth from the flavor factories and the Tevatron experiments. In addition, there is a lot to say about particle astrophysics – dark matter detectors, the launch of GLAST, neutrinos.
The Tevatron Higgs searches are approaching that critical period where the two experiments, combined, are ruling out Standard Model Higgs at certain mass points. Currently, the strongest exclusion is >95% exclusion of the Standard Model Higgs at 170 GeV/c2. This doesn’t sound like much, but it means that with 6-8/fb of data (more than twice what they now have) they stand a serious chance of doing the same at many more mass values. More importantly, they stand a serious chance of seeing something. With current constraints on the Higgs mass requiring it to be below 150-190 GeV/c2, this is growing to a crecendo.
The flavor factories have had a lively back-and-forth on a number of topics, including rare decays, new states of matter, and CP violation. For my money, the most interesting results were on the properties of the VERY rare B decay B -> K(*)ll, which shows some tension with the Standard Model [1]. The larger Belle data sample, when compared to the BaBar data sample, confirms some features of this decay and has tension with others. Belle’s latest search for B -> tau nu, an important rare decay, also led to questions from old hands at the technique like me and other BaBarians [2]. There is definitely something going on with the Belle result, but more information is needed to understand the concreteness of their results. Finally, the claimed observation of a state called the Z(4430) from Belle a year ago is in some question with BaBar’s latest study of the final states involved in this alleged particle [3]. BaBar seems to refute its existence, and a lively discussion ensued at the parallel session where this was presented.
I’m very proud of the results from the Upsilon sample that have been shown by BaBar at this conference. We have unveiled our scan of the parameter Rb [4], which tells us about the rich structure of hadron production above the Y(4S) resonance and which is nearly unparalleled in its resolution. We have shown the results of the search for the eta_b [4], with a full plenary talk this coming Tuesday [5]. We have also shown our first results in the search for new physics, a light, invisible Higgs, which I had the pleasure of presenting in a parallel session talk [6].
The excitement is not over. Tomorrow, we have a full plate of plenaries and Tuesday we conclude with hot results from several experiments!
[1] B -> K(*)ll from BaBar and Belle
[2] B -> tau nu from Belle
[3] The Z(4430) from Belle and BaBar
[4] Rb and the eta_b from BaBar
[5] Plenary on the eta_b
[6] Search for Y(3S) -> gamma A0 from BaBar
