# The Coldest Place in Westerville

Last week Dr. Reinhard and his students detected ultracold rubidium atoms in a magneto-optical trap for the first time. The atoms, seen below with an infrared sensitive camera, have a temperature of about 100 micro Kelvin, or about a million times colder than room temperature. For reference, the surface of the sun is only about 20 times hotter than room temperature.

# Full of Liquid Argon

The MicroBooNE detector is now full of liquid argon!

Nine tanker trucks put 34,000 gallons of liquid argon into the detector, finishing July 9. The fill was carefully watched by everyone at Fermilab, with Dr. Tagg’s silly but useful webpage. (Warning: soundtrack.)

http://argo-microboone.fnal.gov/FillLevel/

# How Physics Will Change—and Change the World—in 100 Years

Interesting and inspiring article on the (history and) future of physics by Frank Wilczek.

# Operation Physics in full swing for 2015-16

OP2: Operation Physics, a crash course in physics for middle school science teachers, is underway now at Otterbein. The course features many hands-on activities and the teachers receive loads of gear for teaching science. The program is supported by a grant from the Ohio Board of Regents, and is in its 6th year at Otterbein.

# Relatively Funny

A student riding in a train looks up and sees Einstein sitting next to him. Excited, he asks, “Excuse me, professor. Does Boston stop at this train?”

# 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.