# First collisions at 13 TeV as the Large Hadron Colllider restarts

On May 21, 2015 proton beams were collided together in the Large Hadron Collider at the record energy of 13 TeV, as the LHC restarts after extensive upgrades over the past two years.  This is the total energy in the center-of-mass frame, so each beam contains protons of energy 6.5 TeV.  That’s about 6,500 times the rest energy of a proton (roughly 1 GeV), hence the relativistic gamma factor for these protons is about 6,500.

Read the CERN article on this important milestone here.

# Higgs boson paper has 5,154 authors

CMS and Atlas, the two big experimental collaborations at the Large Hadron Collider, have joined forces to produce the most accurate determination of the Higgs boson mass to date.  By combining their data sets they obtained

$$M_H=125.09\pm0.24~GeV$$

for a relative error of about 0.2%.  The paper in Physical Review Letters describing these results has the longest author list ever: 5,154 names.  In the published version, there are 9 pages describing the research and 24 pages of authors and their affiliations.

Read the associated APS Physics Viewpoint article here.

# Why small colleges (like Otterbein!) are great for college students

Lots of great points in this article, including the perhaps counter-intuitive one that there is often a greater opportunity for meaningful research experiences at small institutions than at large, research-oriented universities.

# Rubidium atoms cooled to new record low temperature

A cloud of Rb atoms in a Stanford physics lab has become the coldest stuff on Earth.  At about 50 trillionths of a kelvin (50 pK), the atoms’ temperature was roughly ten times smaller than the previous record.

Read the abstract of the paper in Physical Review Letters here.

# OSAPS Meeting this weekend

This weekend, March 27&28, 2015, will see the Spring Meeting of the Ohio-Region Section of the American Physical Society (OSAPS) at Kent State University.  The focus will be on “The Physics of the QCD Phase Diagram”. All information is online at: http://cnr2.kent.edu/OSAPS/.

The  conference is a Friday afternoon/Saturday morning event, and free for students. Although there is a set of plenary talks on the main theme of the meetings, many short talks with topics from all areas of physics are scheduled in the parallel sessions.

The OSAPS conferences (one in spring plus one in fall every year) are a great opportunity for undergrads to go a first professional conference.

# It’s official: Rocky Mountains safest spot to hide from US zombie outbreak

Cornell University physicists have analyzed the statistical mechanics of zombies, and suggest that in the event of a zombie outbreak the best place for Americans to hide during the full-scale takeover would be the northern Rockies – or just about anywhere but a major city. Read the associated 2015 APS March Meeting abstract.

# Neutrinos in the Classroom

The MINERvA EPO project is finally ready for release.  Here it is, after lots of hard work by many people:

http://neutrino-classroom.org

This resource allows one to teach particle decay and momentum conservation principles using real data from the MINERvA neutrino experiment!

It’s so pretty.