Michael Longo

E-Mail: mlongo at umich.edu

Professor of Physics, University of Michigan


Experimental High-Energy Physics, astrophysics.

For the past few years, I have worked primarily in astrophysics, in particular analyzing data from the Sloan Digital Sky Survery (SDSS). This has led to strong evidence for a cosmic parity violation in the Universe, as indicated by a statistically significant excess of left-handed spiral galaxies toward the north Galactic pole and an excess of right-handed in the opposite direction. This also suggests that our Universe has an axis and a net angular momentum. By angular momentum conservation this means the Universe was born spinning. We can't see outside of our Universe, so we'd have to assume it is spinning relative to other universes in a higher dimensional space. Presumably the Big Bang was spinning intially, and as it expanded the net angular momentum was dissipated among the galaxies. Now we still see it through the preferred spin direction. [See, Detection of a Dipole in the Handedness of Spiral Galaxies with Redshifts z ~ 0.04, (Michael J. Longo), Phys. Lett. B 699, 224-229 (2011).]

Previously my primary research activities have been experiments at Fermilab, including E871 (HyperCP), an experiment designed to perform a sensitive search for direct CP violation in the decays of Xi and Lambda hyperons by looking for an asymmetry between particle and antiparticle decay parameters. Research Fellow H.K. Park prepared a paper with results on rare decays of kaons involving two muons, which was the first published result from HyperCP (http://ppd.fnal.gov/experiments/e871). I analyzed the HyperCP data to search for the so-called Theta(1.54) pentaquark state. The negative result from this search showed that this state, though reported by several previous experiments, did not exist. HyperCP has come up with a fascinating hint of new physics in the form of a possible sighting of a low-mass sgoldstino in the decay Sigma+ -> p mu+ mu-. There are only three events but they are very clean, so there is little doubt they are genuine. The amazing thing is that all 3 events give the same reconstructed dimuon mass to within 1 MeV which is the experimental resolution. The probability of this happening by chance is 0.8%. Another hint of new physics is that the branching ratio appears to be larger than expected in the Standard Model.

I'm also on the MIPP experiment at Fermilab. This is an experiment to measure cross sections for production of protons, neutrons, pions, kaons etc. by beams of particles with energies up to 100 GeV.

I was part of the MACRO collaboration. This is a large underground detector under the Gran Sasso in Italy. We built most of the liquid scintillation counters that covered the vertical faces of the detector. .

The picture above shows the MACRO detector under construction. Our scintillator tanks are stacked up in the right foreground. The detector is now dismantled, but it was fun and a good excuse to go to Italy!

For a list of my publications (over 300 at last count), go to INSPIRE.

For my publications with more than 50 citations, go to TOPCITE.

To send mail to me, send to MLongo at UMICH.EDU.

  • Meet my wife Faye!
  • Rayna,Rachel, Maketa,Cassie,& Kyle, 5/2002.
  • For more on the Longo family, go to Longo family web page.

    or, Gene and Debbie's page.

    What's New

    My first grand-daughter Rachel was born on May 10, 1998.
  • Rachel on a blanket!

    Maketa Lea was born to Kathy and Jim on July 8, 1999 .

  • Maketa Lea Mattimore at age 2 mo with Rachel

  • Maketa & Kyle Mattimore, Cassie & Rachel Longo, ca. July, 2001.

  • Faye & I with Gene and Debbie's new daughter, Rayna, b. ca. 7/2/2001.

    Julianna Longo was born to Sally & Michael in October,2003. Here she is with her two sisters.

  • Julianna with Rachel and Cassie (and Hammie).

  • Me with 5 granddaughters, June, 2014.

    Other Places in Webspace

    HyperCP experiment web page, HyperCP.

    MIPP experiment web page, MIPP Experiment.

    For more on UM Physics try UM Physics.

    Last updated on July, 2014

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