Glennys Farrar

Professor Of Physics; Collegiate Professor

Education/Bio

Glennys R. Farrar is a Collegiate Professor of Physics and Julius Silver, Rosalind S. Silver and Enid Silver Winslow Professor at New York University. She received her B.A. in Physics from the University of California (Berkeley) in 1967 and Ph. D. in Physics from Princeton University in 1971, the first woman to do so. She was a Member of the Institute for Advanced Study from 1971-1973, then Research Scientist at Caltech from 1973-1974. She was promoted to Assistant Professor at Caltech in 1974, but was converted to Senior Research Scientist in 1977, being told that was necessary to avoid that she would come up for tenure review. She joined the faculty of Rutgers University in 1979, then moved to NYU in 1998 to be Chair of the Physics Department . In 2001 she founded the Center for Cosmology and Particle Physics and served as its Director for seven years. Farrar is a recent Chair of the Division of Astrophysics of the American Physical Society and was a member of the Snowmass 2021 Steering Committee and has been a long-time editor of the Journal of Cosmology and Particle Physics. She is a Fellow of APS and AAAS; received Sloan, Guggenheim and Simons Fellowships; serves on advisory panels for NASA, NSF and the European Research Council. She was elected to the (U.S.) National Academy of Sciences in 2023.

Areas of Research/Interest

Farrar's primary research goal is discovering the identify of the Dark Matter which comprises more than 80% of the matter in the Universe, yet does not contain protons and neutrons making it fundamentally different than any known type of matter. She is currently investigating whether it can be composed of quarks in a hard-to-discern form that has eluded discovery, or must be evidence of an entirely new sub-nuclear world as usually assumed. Other interests are the origin of the excess of matter over anti-matter (without which the Universe would be devoid of galaxies, stars and life), the strong CP puzzle (why the neutron electric dipole moment is a billion times smaller than expected), the origin of the Galactic magnetic field and sources of Ultrahigh Energy Cosmic Rays (UHECRs).

Prof. Farrar has made seminal contributions to theoretical particle physics, including demonstrating that quarks are not just mathematical constructs but are actually physically present in matter (Brodsky-Farrar 1973) and pioneering the search for supersymmetry (Farrar-Fayet 1976), a prime objective of the Large Hadron Collider. With students she also made fundamental contributions to astrophysics: discovering the existence of an unexpected large-scale poloidal component of the magnetic field of the Milky Way (Jansson-Farrar 2012) and uncovering the first unambiguous examples of “stellar tidal disruption” when a supermassive black hole tears a passing star to shreds (vanVelzen-Farrar+ 2011). She proposed (with Gruzinov, 2009) that transient events may be the primary source of UHECRs, co-authored (as part of the Pierre Auger Collaboration) the influential paper on multi-messenger observations of the binary neutron star merger GW170817, and co-authored a paper (Stein et al, 2021) reporting the coincident arrival of an astrophysical neutrino with a tidal disruption event.

Farrar's current work centers on QCD, Dark Matter, Ultrahigh Energy Cosmic Rays, and the magnetic field of the Milky Way. Primariliy with students and postdocs, she has placed important indirect constraints on the sources of UHECRs (Ding, Globus, Farrar 2021; Muzio-Farrar 2023), interactions of DM with baryons (Xu, Wang, Farrar in various combinations, 2021-2023) and with KIT senior researcher Unger has developed a new suite of models of the Galactic magnetic field (Unger, Farrar 2023) .

Selected Publications

Auger papers not included; [Google Scholar citations on 03/17/22 ]

  1. “Scaling Laws at Large Transverse Momentum”, S. J. Brodsky and G. R. Farrar, Phys. Rev. Lett. 31, 1153 (1973) [2335] and
    “Scaling Laws for Large Momentum Transfer Processes”, Phys. Rev. D 11, 1309 (1975). [1162]
  2. “Particle Ratios in Energetic Hadron Collisions”, J. D. Bjorken and G. R. Farrar, Phys. Rev. D 9, 1449 (1974). [142]
  3. “Pion and Nucleon Structure Functions Near x=1”, G. R. Farrar and D. R. Jackson, Phys. Rev. Lett. 35, 1416 (1975). [673]
  4. “Copious Direct Photon Production as a Possible Resolution of the Prompt Lepton Puz- zle”, G. R. Farrar and S. C. Frautschi, Phys. Rev. Lett. 36, 1017 (1976). [135]
  5. “Phenomenology of the Production, Decay, and Detection of New Hadronic States Asso- ciated with Supersymmetry”, G. R. Farrar and P. Fayet, Phys. Lett. B 76, 575 (1978) [3181] and
    “Bounds on R-hadron production from calorimetry experiments”, Phys. Lett. B 79, 442 (1978) [159] and
    “Searching for the spin-0 leptons of supersymmetry”, Phys. Lett. B 89, 191 (1980) [133]
  6. “The Pion Form-Factor”, G. R. Farrar and D. R. Jackson, Phys. Rev. Lett. 43, 246 (1979). [544]
  7. An alternative to perturbative grand unification: How asymptotically non-free theorues can successfully predict low-energy gauge couplings, N. Cabbibo and G. R. Farrar, Phys. Lett. B 110, 107 (1982) [62].
  8. Supersymmetry at ordinary energies. II. invariance, Goldstone bosons, and gauge-fermion masses, G. R. Farrar and S. Weinberg, Phys. Rev. D 27, 2732 (1983) [151]
  9. “Transparency in Nuclear Quasiexclusive Processes with Large Momentum Transfer”, G. R. Farrar, H. Liu, L. L. Frankfurt and M. I. Strikman, Phys. Rev. Lett. 61, 686 (1988). [312]
  10. Recursive stratified sampling for multidimensional Monte Carlo integration, W. H. Press and G. R. Farrar, Computers in Physics 4,202 (1990). [137]
  11. “Light gluinos”, G. R. Farrar, Phys. Rev. Lett. 53, 1029 (1984). [97] “Experiments to find or exclude a long lived, light gluino”, Phys. Rev. D 51, 3904 (1995) [153] and
    “Detecting gluino-containing hadrons”, Phys. Rev. Lett. 76, 4111 (1996). [191]
  12. “Determining the gluonic content of isoscalar mesons”, F. E. Close, G. R. Farrar and Z. p. Li, Phys. Rev. D 55, 5749 (1997) [271]
  13. “SUSY and the electroweak phase transition”, G. R. Farrar and M. Losada, Phys. Lett. B406, 60 (1997) [105]
  14. “Baryon asymmetry of the universe in the minimal Standard Model,” G. R. Farrar and M. E. Shaposhnikov, Phys. Rev. Lett. 70, 2833-2836 (1993) [370] and
    “Baryon asymmetry of the universe in the standard electroweak theory,” Phys. Rev. D 50, 774 (1994) [441]
  15. “Soft Yukawa couplings in supersymmetric theories”, F. Borzumati, G. R. Farrar, N. Polonsky and S Thomas, Nucl. Phys. B555,53 (1999). [232]
  16. “Self-interacting dark matter”, B .D. Wandelt, R. Dave, G. R. Farrar, D. N. Spergel and P. J. Stein- hardt, Sources and detection of dark matter and dark energy in the universe, pp 263-274 (2001). [143]
  17. “Interacting dark matter and dark energy”, G. R. Farrar and P. J. E. Peebles. Astrophys. J. 604, 1 (2004). [487]
  18. “The 2dF Galaxy Redshift Survey: luminosity functions by density environment and galaxy type”, D. J. Croton, G. R. Farrar et al, MNRAS 356,1155 (2005) [324] and
    “Where do ‘red and dead’ early-type void galaxies come from?”, MNRAS 386, 2285 (2008).[62]
  19. “Window in the dark matter exclusion limits”, Phys. Rev. D 72, 083502 (2005) [90.]
  20. “Dark matter and the baryon asymmetry”, G. R. Farrar and G. Zaharijas. Phys. Rev. Lett. 96, 041302 (2006). [179]
  21. “A New Force in the Dark Sector?” G. R. Farrar and R. A. Rosen, Phys. Rev. Lett. 98, 171302 (2007), [101]
    “The Speed of the bullet in the merging galaxy cluster 1E0657-56”, V. Springel and G. Farrar. Mon. Not. Roy. Astron. Soc. 380, 911 (2007); [240]
    “Constrained Simulation of the Bullet Cluster” C. Lage and G. R. Farrar, Astrophys. J., 787,14 (2014) [48] and
    “The Bullet Cluster is not a Cosmological Anomaly”, JCAP 2,38 (2015). [29]
  22. “Giant AGN flares and cosmic ray bursts”, G R Farrar and A. Gruzinov Astrophysical J. 693, 329 (2009). [168]
  23. “Optical discovery of probable stellar tidal disruption flares”, S. van Velzen, G. R. Farrar, et al., Astrophysical J. 741, 73 (2011) [317] and
    “Measurement of the rate of stellar tidal disruption flares,” S. van Velzen and G. R. Farrar, Astrophys. J. 792, 53 (2014) [125] and
    “A tidal disruption event coincident with a high-energy neutrino,” R. Stein, S. Van Velzen, M. Kowalski, ... G. Farrar et al., Nature Astron. 5, no.5, 510-518 (2021) [65].
  24. “A New Model of the Galactic Magnetic Field”, R. Jansson and G. R. Farrar, Astrophys. J., 757,144 (2012) [633] and
    “The Galactic Magnetic Field,” Astrophys. J. Lett. 761, L11 (2012) [580].
  25. “Origin of the ankle in the ultrahigh energy cosmic ray spectrum, and of the extragalactic protons below it”, M. Unger, G. R. Farrar, L. A. Anchordoqui Phys. Rev. D 92 , 123001 (2015) [136] and
    “Probing the environments surrounding ultrahigh energy cosmic ray accelerators and their implications for astrophysical neutrinos,” M. S. Muzio, G. R. Farrar and M. Unger, Phys. Rev. D 105, no.2, 023022 (2022).
  26. “Testing hadronic interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory”, The Pierre Auger Collaboration, G. R. Farrar corresponding author, Phys. Rev. Lett. 117,192001 (2016). [223]
  27. “Multi-messenger Observations of a Binary Neutron Star Merger,”, B. P. Abbott et al. [LIGO Scientific, Virgo, Fermi GBM, INTEGRAL, IceCube, AstroSat Cadmium Zinc Telluride Im- ager Team, IPN, Insight-Hxmt, ANTARES, Swift, AGILE Team, 1M2H Team, Dark Energy Camera GW-EM, DES, DLT40, GRAWITA, Fermi-LAT, ATCA, ASKAP, Las Cumbres Observatory Group, OzGrav, DWF (Deeper Wider Faster Program), AST3, CAASTRO, VINROUGE, MASTER, J-GEM, GROWTH, JAGWAR, CaltechNRAO, TTU-NRAO, NuSTAR, Pan-STARRS, MAXI Team, TZAC Consortium, KU, Nordic Optical Telescope, ePESSTO, GROND, Texas Tech University, SALT Group, TOROS, BOOTES, MWA, CALET, IKI-GW Follow-up, H.E.S.S., LOFAR, LWA, HAWC, Pierre Auger, ALMA, Euro VLBI Team, Pi of Sky, Chandra Team at McGill University, DFN, ATLAS Tele- scopes, High Time Resolution Universe Survey, RIMAS, RATIR and SKA South Africa/MeerKAT], Astrophys. J. Lett. 848, no.2, L12 (2017). [2056]
  28. “Dark Matter that Interacts with Baryons: Density Distribution within the Earth and New Constraints on the Interaction Cross-section”, D. A. Neufeld, G. R. Farrar and C. F. Mc- Kee, Astrophys. J., 866,111 (2018). [21]
  29. “Gas-rich dwarf galaxies as a new probe of dark matter interactions with ordinary mat- ter,” D. Wadekar and G. R. Farrar, Phys. Rev. D 103, no.12, 123028 (2021) [14].
  30. “The Imprint of Large Scale Structure on the Ultra-High-Energy Cosmic Ray Sky”, C. Ding, N. Globus and G. R. Farrar, Astrophysical J. Letters, 913, L13, (2021) [5].
  31. “Resonant Scattering between Dark Matter and Baryons: Revised Direct Detection and CMB Limits,”, X. Xu and G. R. Farrar, [arXiv:2101.00142 [hep-ph]] and
    “Constraints on GeV Dark Matter interaction with baryons, from a novel Dewar exper- iment,” [arXiv:2112.00707 [hep-ph]].
  32. A Stable Sexaquark: Overview and Discovery Strategies, G R Farrar, [arXiv:2201.01334 [hep-ph]].