Physics

A Sense Of Scale

Apr 10 2013 | 7 comment(s)

There have been other attempts in the past, so this is not strictly a new idea. However I found the interactive web page at http://htwins.net/scale2/ extremely well constructed.

It is a graphical display of the largest and smallest structures from galaxy superclusters down to quarks and the Planck length. By moving a scroll bar left or right, you can get a very clear sense of scale of the different things. And in so doing you learn the relative size of different objects, from planets to stars, or from stars to galaxies; or vice-versa, from cells to molecules and atoms.

I highly recommend it!

Sterile Neutrinos: Toward A Clarifying Experiment

Apr 09 2013 | 22 comment(s)

Now that the Higgs has been found, the current hype in popular science magazines suggests that the most pressing question in fundamental physics research is whether new particles will be found at the Large Hadron Collider: Is Supersymmetry the right extension of the standard model? Or are there new extra dimensions of space-time ? Can microscopic black holes be created in particle collisions ? I think all of you have heard some of these questions enough times by now.

11 Electron Neutrinos In T2K!

Apr 04 2013 | 8 comment(s)

The T2K Collaboration released today an analysis of their data in the Cornell Arxiv. T2K searches for electron neutrinos appearing in a muon neutrino beam produced by the J-PARC accelerator facility in Tokai-Mura, using a near detector located 280 meters downstream of the proton target, and a far detector (SuperKamiokande) at 295 km from the source.

The appearance of electron neutrinos in a muon neutrino beam is a very important oscillation signal of neutrinos, that allows the measurement of the parameter theta_13, one of the so far less-well known parameter of the neutrino mixing matrix.

Dark matter non-results of the Alpha Magnetic Spectrometer and ANTARES. What these two observations really mean for dark matter.

Apr 04 2013 | 7 comment(s)

The Alpha Magnetic Spectrometer has found is that there are interesting features in the cosmic ray background which could indicate dark matter particle anti particle annihilations. That is not the same as finding dark matter. The ANTARES neutrino telescope was used to take observations of the solar neutrino flux with directionality, which found no excess of neutrinos from the sun (http://arxiv.org/abs/1302.6516). That would have indicated dark matter concentrated at the center of mass of our solar system. Taken together these results indicate that many of our assumptions on the nature of dark matter are wrong.

The Higgs Lottery

Apr 02 2013 | 1 comment(s)

The mediatic effect of the Higgs boson discovery of last July is clear to everybody. And CERN has been very good at exploiting it, making fundamental physics a familiar topic and creating interest worldwide. Yet I think we can do more. The gap between basic research in physics and the public is wide, and we are doing still too little to fill it.

Two Higgs After All ? A New Signal From CMS !

Apr 01 2013 | 15 comment(s)

What looks like a tantalizing signal of the rare two-muon decay of the Higgs boson has been evidenced in an analysis of 2011+2012 data just sent to PRL by the CMS collaboration. This analysis targeted supersymmetric neutral Higgs bosons, whose decay to muon pairs is enhanced for some values of the SUSY parameters, but was not expecting to see any signal in the 25 inverse femtobarns of collisions that the CMS experiment has so far collected.

The Light Matter Proposal: The Effect of Fusion on the Velocity Profile of a Disk Galaxy

Mar 31 2013 | 23 comment(s)

The Problem with Velocity Profiles

The velocity profile of thin disk galaxies is a riddle worth pondering. Studies have shown that the velocity of stars in a galaxy rise to a peak as one leaves the center, and then stays flat as one looks further out. Newtonian gravitational theory can predict the peak correctly, but there must always be a decline.

From Galaxy rotation curve, with A is the Newtonian prediction, B is the data.

Eventually, The Tevatron Also Sees The Higgs!

Mar 27 2013 | 17 comment(s)

I think I wrote a post about the "definitive results" of the CDF and DZERO experiments on the search for the Higgs boson at least a couple of times already in the past, but you know, these busy experimentalists continue to improve their analyses, adding previously incomplete information, combining results, tweaking and improving things here and there. It is only natural that on such an important topic as the observation of the Standard Model Higgs boson the Tevatron folks were not ready to give up just yet.

Are Physics Conferences A Waste ? An Ethical Issue

Mar 25 2013 | 36 comment(s)

The number of conferences held every year around the world to present and discuss topics in frontier particle physics is surprisingly large: over a hundred per year. Just look at the following list of conferences scheduled in the last three weeks for a proof (and no, March is not very different from other months):

2/3 Moriond EWK
4/3 KEKPH 2013
4/3 DPG 2013
9/3 Moriond QCD
10/3 Aspen 2013
10/3 HiJetsUSC 2013
13/3 LHCC
17/3 LISHEP 2013
18/3 MITP 2013
21/3 HFMCW 2013
21/3 DPHEP7 2013

Planck confirms WMAP results, and is largely silent on theoretical astrophysics.

Mar 22 2013 | 10 comment(s)

From the perspective of one theoretical particle physicist Planck found far from "nothing". The ESA's Planck probe largely corroborates the findings of NASA's WMAP probe, but it leaves theoretical astrophysics unsettled. After reading my fellow blogger Dr. Tommaso Dorigo's coverage of the Planck announcement I was unsure how to react. We can only conclude that the Planck mission has largely confirmed WMAP's results. Just this kind of confirmation is a basic step in the scientific method.