With great excitements I arrived at Palais des Congres this morning for Day One at ICHEP. Most of the talks today were outside of my area of research. This is a good thing in a sense as it means that I may get to learn new things from the talks. And yes, it was indeed the case. On the experimental side, I have enjoyed the well attended Tevatron Higgs session this afternoon on updated limits in both the high and low mass regions from CDF and D0. On the theory side, the highlight was the talk on Emergent Gravity by Erik Verlinde based on the paper (arXiv:1001.0785) he wrote earlier this year claiming that
"Gravity is not a fundamental force"
but it emerges as an entropic force caused by changed in the information associated with the positions of material bodies. Given that this claim changes fundamentally how we think about gravity, there were many very critical questions from the audience as you can imagine, such as the scale at which the entropic interpretation breaks down, the role of graviton in this scenario, the equivalence of the entropic scenario and other known theories in which gravity is a fundamental force.
As pointed out by my fellow bloggers as well that the most important thing being at conferences probably is to interact with other physicists face to face. Besides the coffee breaks, poster sessions also provide such an opportunity to informally discuss and learn new results and ideas from one another.
So what did I learn during the poster session today??
"Is there LSND anomaly?"
According to Poster # 588 from Harp - CDP, which presents the new results they just released a few weeks ago on the low energy pion backgrounds, the answer is NO. What they found is that there is a significant asymmetry in producing pi+ and pi-. The effects of this was not taken into account by LSND, according to the poster. More specifically, LSND underestimated the backgrounds by a factor of 2 and it underestimated the systematic errors by at least by a factor of 2, according to Poster #588. If the analysis stands, the still unanswered question then is, could the excess seen by MiniBoone in both the neutrino and antineutrino modes similarly due to the low energy pion backgrounds?
Tomorrow will be an exciting day as well. It will start out with presentations on first physics results from the LHC. Very much looking forward to it!
I would like to know what Geoffrey Mills (MiniBooNE) have to say about the possible absence of LNSD signal. It would be great if you ask him on Saturday and let the rest of the world know.
ReplyDeleteThanks
That HARP poster doesnt appear to be available. Interestingly according to your report it seems to come to opposite conclusions to arXiv:0810.1398
ReplyDeleteThere seems to be some controversy within HARP? Do you know anything about arXiv:0909.2745 and arXiv:0903.4762 ? Do you know which HARP faction is responsible for this analysis?
The poster is signed "Alexey Zemchugov for the HARP-CDP group".
ReplyDeleteInteresting about LSND!! Thanks!
ReplyDeleteI talked to Geoff on yesterday and was told that he has been in close contact with Alexey and he thinks that the recent result from HARP-CDP group is interesting. According to Geoff, LSND used the same simulation tool (GEANT 3) as one of the two simulations used in the recent results from HARP-CDP (I will post the version number of GEANT used by HARP-CDP later today, though I vaguely remember it is a later version GEANT4), and did not see such a big factor in the asymmetry. I will post more details once I have learned more and fact-checked.
ReplyDeleteAnd I should add that according to Geoff, this is a very complicated process. He and Alexey will go through the analyses together and try to find out what the sources of the discrepancies are.
ReplyDeleteMany thanks Mu-Chun!
ReplyDeleteI thought that this blog would be just a good way to make jealous all of us who could not attend the conference but now I feel represented there! Please let us know any update about this. To be honest, I do not feel confident with results that are not supported by the collaboration, that is why I wanted to know the opinion of someone in MiniBooNE. Thanks again and I look forward to more updates about this topic, you guys are doing a great job!
Just talked to G Garvey, who says this poster is incorrect--the negative pions get absorbed before they decay. In fact he says LSND overestimated the background.
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