* Astronomy

Blobrana · L

RE: Large Hadron Collider

Blobrana · L

Higgs hunt results excite scientists

The Large Hadron Collider (LHC) has picked up tantalising fluctuations which might - or might not - be hints of the sought-after Higgs boson particle.
But scientists stress caution over these "excess events", because similar wrinkles have been detected before only to disappear after further analysis.
Either way, if the sub-atomic particle exists it is running out of places to hide, says the head of the European Organization for Nuclear Research (Cern), which runs the LHC.
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Blobrana · L

LHC achieves 2011 data milestone

Today at around 10:50 CEST, the amount of data accumulated by LHC experiments ATLAS and CMS clicked over from 0.999 to 1 inverse femtobarn, signalling an important milestone in the experiments' quest for new physics. The number signifies a quantity physicists call integrated luminosity, which is a measure of the total number of collisions produced. One inverse femtobarn equates to around 70 million million collisions, and in 2010 it was the target set for the 2011 run. That it has been achieved just three months after the first beams of 2011 is testimony to how well the LHC is running.
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Blobrana · L

LHC experiences close encounters with UFOs

On 29 May, yet another record was set as 1092 bunches per beam were injected into the LHC, hitting a peak luminosity of 1.26x10^33 cm^-2 s^-1. While running at 3.5 TeV each beam now packs a total energy of over 70 MJ - equivalent to a TGV travelling at a 70 kph.
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Blobrana · L

Scientists at the Large Hadron Collider have succeeded in trapping atoms of anti-hydrogen for more than 15 minutes - a breakthrough in the quest to learn about the origins of the universe.
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Blobrana · L

Title: Light Sneutrino Dark Matter at the LHC
Authors: Geneviève Bélanger, Sabine Kraml, Andre Lessa

In supersymmetric (SUSY) models with Dirac neutrino masses, a weak-scale trilinear A-term that is not proportional to the small neutrino Yukawa couplings can induce a sizable mixing between left and right-handed sneutrinos. The lighter sneutrino mass eigenstate can hence become the lightest SUSY particle (LSP) and a viable dark matter candidate. In particular, it can be an excellent candidate for light dark matter with mass below ~10 GeV. Such a light mixed sneutrino LSP has a dramatic effect on SUSY signatures at the LHC, as charginos decay dominantly into the light sneutrino plus a charged lepton, and neutralinos decay invisibly to a neutrino plus a sneutrino. We perform a detailed study of the LHC potential to resolve the light sneutrino dark matter scenario by means of three representative benchmark points with different gluino and squark mass hierarchies. We study in particular the determination of the LSP (sneutrino) mass from cascade decays involving charginos, using the mT2 variable. Moreover, we address measurements of additional invisible sparticles, in our case the lightest neutralino, and the question of discrimination against the MSSM.

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Blobrana · L

Higgs boson result 'false alarm'

Reports that the Large Hadron Collider had detected the first possible signs of the elusive Higgs boson particle were "wrong", experts have said.
Last month, an internal memo outlining a possible signal from the Higgs picked up at the LHC was leaked on to the web.
But cross-checks of the data collected by the Atlas experiment have since found no signal.
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Blobrana · L

Data leaks from particle hunters raise questions about scientific trust.

In late April, leaked results from the Large Hadron Collider (LHC), the world's largest particle accelerator, seemed to show a preliminary signal of the Higgs boson. A fresh analysis published this week has debunked the claim, but researchers are bracing themselves for a string of other false alarms to appear on blogs over the coming months.
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Blobrana · L

Higgs speculation is 'premature'

Speculation about a dramatic finding in the search for the elusive Higgs boson particle is premature, experts say.
An internal note leaked on the web reveals that a group of researchers at the Large Hadron Collider (LHC) has detected a signal compatible with the sought-after particle.
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Blobrana · L

A commenter on the previous posting has helpfully given us the abstract of an internal ATLAS note claiming observation of a resonance at 115 GeV. Its the sort of thing you would expect to see if there were a Higgs at that mass, but the number of events seen is about 30 times more than the standard model would predict. Best guess seems to be that this is either a hoax, or something that will disappear on further analysis.
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