Biography:Christopher T. Hill

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Short description: American theoretical physicist
Christopher T. Hill
ChristopherTHillphysics.jpg
Born (1951-06-19) June 19, 1951 (age 72)
Neenah, Wisconsin
NationalityAmerican
Alma materM.I.T.
Caltech
Known forInfrared fixed point of the top quark; Topcolor; Top quark condensate; Dimensional deconstruction; Chiral symmetry breaking in Heavy-Light Mesons; Theory of UHE Cosmic Rays; Soft Nambu-Goldstone Boson model of Dark Matter.
Scientific career
InstitutionsFermilab
Doctoral advisorMurray Gell-Mann

Christopher T. Hill (born June 19, 1951) is an American theoretical physicist at the Fermi National Accelerator Laboratory who did undergraduate work in physics at M.I.T. (B.S., M.S., 1972), and graduate work at Caltech (Ph.D., 1977, Murray Gell-Mann[1]). Hill's Ph.D. thesis, "Higgs Scalars and the Nonleptonic Weak Interactions" (1977) contains one of the first detailed discussions of the two-Higgs-doublet model and its impact upon weak interactions.[2]

Hill is an originator, with William A. Bardeen and Manfred Lindner, of the idea that the Higgs boson is composed of top and anti-top quarks. This emerges from the concept of the top quark infrared fixed point,[3] which predicted (1981) that the top quark would be very heavy, contrary to most popular ideas at the time. The fixed point prediction lies within 20% of the observed top quark mass (1995). This implies that the top quarks may be strongly coupled at very short distances and could form a composite Higgs boson, which led to top quark condensates,[4] topcolor,[5][6] and also dimensional deconstruction, which is a renormalizable, lattice description of extra dimensions of space.[7] Several new heavy Higgs bosons, such as the b-quark Higgs bound state, may be accessible to the LHC.[8] [9] [10]

Hill coauthored (with Elizabeth H. Simmons) a comprehensive review of strong dynamical theories and electroweak symmetry breaking that has shaped many of the experimental searches for new physics at the Tevatron and LHC.[11]

Heavy-light mesons contain a heavy quark and a light anti-quark, and provide a window on the chiral symmetry dynamics of a single light quark. Hill and Bardeen showed that the (spin)Template:Super [math]\displaystyle{ (0^-,1^-) }[/math] ground states are split from the [math]\displaystyle{ (0^+,1^+) }[/math] parity partners by a universal mass gap of about [math]\displaystyle{ ~ \Delta M \approx 350 \text{ MeV,}~ }[/math] due to the light quark chiral symmetry breaking.[12] This correctly predicted an abnormally long-lived resonance, the [math]\displaystyle{ D_s^*(2317) }[/math] and numerous decay modes which have been confirmed by experiment.[13] Similar phenomena should be seen in the [math]\displaystyle{ B_s }[/math] mesons and [math]\displaystyle{ ccq, bcq, bbq }[/math] (heavy-heavy-light baryons).

Hill has done extensive work on topological interactions and, with collaborators, obtained the full Wess-Zumino-Witten term for the Standard Model, including pseudoscalars, spin-1 vector mesons, and the [math]\displaystyle{ W^\pm }[/math] and [math]\displaystyle{ Z^0 }[/math]. This revealed new anomalous interactions such as [math]\displaystyle{ \nu + X \rightarrow \nu+ \gamma + X }[/math] where [math]\displaystyle{ X }[/math] is a heavy nucleus.[14]

He is also an originator of cosmological models of dark energy and dark matter based upon ultra-low mass bosons associated with neutrino masses and was first to propose that the cosmological constant is connected to the neutrino mass, as [math]\displaystyle{ \Lambda\sim m_\nu^4 }[/math].[15] [16] and has developed modern theories of the origin of ultra-high-energy nucleons and neutrinos from grand unification relics, such as cosmic strings.[17] [18][19][20] He has also shown that a cosmic axion field will induce an oscillating electric dipole moment for any magnet.[21][22] With Graham Ross he has focused more recently on spontaneously broken scale symmetry (or Weyl symmetry), where the scale of gravity (Planck mass) and the inflationary phase of the ultra-early universe are generated together as part of a unified phenomenon dubbed "inertial symmetry breaking."[23] [24][25]

Hill is Distinguished Scientist Emeritus at Fermilab; Head of the Fermilab Theoretical Physics Department (2005 - 2012); CERN Scientific Associate, Geneva, Switzerland (1987-1988); Fellow of the American Physical Society (elected, 1989);[26] Robert A. Millikan Fellow, Caltech (1972-73); Arthur H. Compton Lecturer, University of Chicago, Spring (1979); Visiting Scholar, Oxford University (1980); Professor of Physics (adjunct), University of Chicago, (1996–2000); Gambrinus Fellow, University of Dortmund, (2005); van Winter Lecturer, University of Kentucky (2009); Visiting Professor, Institut de Fisica Corpuscular, Valencia, Spain (2019).

Hill has authored three popular books with Nobel laureate Leon Lederman about physics and cosmology, and the commissioning of the Large Hadron Collider.

Books

  • Symmetry and the Beautiful Universe, Christopher T. Hill and Leon M. Lederman, Prometheus Books (2005)[1]
  • Quantum Physics for Poets, Christopher T. Hill and Leon M. Lederman, Prometheus Books (2010)[2]
  • Beyond the God Particle, Christopher T. Hill and Leon M. Lederman, Prometheus Books (2013)[3]
  • Google Scholar Profile of Christopher T. Hill [4]

References

  1. "Murray Gell-Mann," Physics Today, (2020); https://physicstoday.scitation.org/doi/10.1063/PT.3.4480 (2020)
  2. "Higgs Scalars and the Nonleptonic Weak Interactions" (1977)
  3. Hill, Christopher T. (1 August 1981). "Quark and lepton masses from renormalization-group fixed points". Physical Review D 24 (3): 691–703. doi:10.1103/PhysRevD.24.691. Bibcode1981PhRvD..24..691H. , inspired by: Pendleton, B.; Ross, G.G. (1981). "Mass and Mixing Angle Predictions from Infrared Fixed points". Phys. Lett. B98 (4): 291. doi:10.1016/0370-2693(81)90017-4. Bibcode1981PhLB...98..291P. 
  4. Bardeen, William A.; Hill, Christopher T.; Lindner, Manfred (1990). "Minimal dynamical symmetry breaking of the standard model". Phys. Rev. D 41 (5): 1647–1660. doi:10.1103/PhysRevD.41.1647. PMID 10012522. Bibcode1990PhRvD..41.1647B. 
  5. Hill, Christopher T. (1995). "Topcolor Assisted Technicolor". Phys. Lett. B 345 (4): 483–489. doi:10.1016/0370-2693(94)01660-5. Bibcode1995PhLB..345..483H. 
  6. Hill, Christopher T. (1991). "Topcolor: top quark condensation in a gauge extension of the standard model". Physics Letters B 266 (3–4): 419–424. doi:10.1016/0370-2693(91)91061-Y. Bibcode1991PhLB..266..419H. 
  7. Hill, Christopher T.; Pokorski, Stefan; Wang, Jing (2001). "Gauge invariant effective Lagrangian for Kaluza-Klein modes". Phys. Rev. D 64 (10): 105005. doi:10.1103/physrevd.64.105005. Bibcode2001PhRvD..64j5005H. http://inspirehep.net/record/541000. 
  8. Hill, Christopher T. (4 April 2014). "Is the Higgs boson associated with Coleman-Weinberg dynamical symmetry breaking?". Physical Review D 89 (7): 073003. doi:10.1103/PhysRevD.89.073003. Bibcode2014PhRvD..89g3003H. 
  9. Hill, Christopher T.; Machado, Pedro; Thomsen, Anders; Turner, Jessica (2019). "Where are the Next Higgs Bosons?". Physical Review D100 (1): 015051. doi:10.1103/PhysRevD.100.015051. Bibcode2019PhRvD.100a5051H. 
  10. Hill, Christopher T.; Machado, Pedro; Thomsen, Anders; Turner, Jessica (2019). "Scalar Democracy". Physical Review D100 (1): 015015. doi:10.1103/PhysRevD.100.015015. Bibcode2019PhRvD.100a5015H. 
  11. Hill, Christopher T.; Simmons, Elizabeth H. (2003). "Strong dynamics and electroweak symmetry breaking.". Phys. Rep. 381 (4–6): 235. doi:10.1016/S0370-1573(03)00140-6. Bibcode2003PhR...381..235H. http://inspirehep.net/record/0203079. 
  12. Bardeen, William A.; Hill, Christopher T. (1994). "Chiral dynamics and heavy quark symmetry in a solvable toy field theoretic model". Physical Review D 49 (1): 409–425. doi:10.1103/PhysRevD.49.409. PMID 10016779. Bibcode1994PhRvD..49..409B. 
  13. Bardeen, William A.; Eichten, Estia; Hill, Christopher T. (2003). "Chiral multiplets of heavy-light mesons". Physical Review D 68 (5): 054024. doi:10.1103/PhysRevD.68.054024. Bibcode2003PhRvD..68e4024B. 
  14. J. A. Harvey, C. T. Hill and Richard Hill, Standard Model Gauging of the Wess-Zumino-Witten Term: Anomalies, Global Currents and pseudo-Chern-Simons Interactions, Phys. Rev. D77 085017 (2007), hep-ph 0712.1230; Anomaly mediated neutrino-photon interactions at finite baryon density, Phys. Rev. Lett. 99, 261601 (2007); hep-ph 0708.1281
  15. Frieman, Joshua A.; Hill, Christopher T.; Stebbins, Albert; Waga, Ioav (1995). "Cosmology with ultralight pseudo Nambu-Goldstone bosons". Phys. Rev. Lett. 75 (11): 2077–2080. doi:10.1103/PhysRevLett.75.2077. PMID 10059208. Bibcode1995PhRvL..75.2077F. 
  16. Hill, Christopher T.; Schramm, David N.; Fry, James N. (1989). "Cosmological Structure Formation from Soft Topological Defects". Comments on Nucl. Part. Phys.. 19. pp. 25–39. http://inspirehep.net/record/264619/files/v19-n1-p25.pdf. 
  17. Hill, Christopher T.; Schramm, David N. (1 February 1985). "Ultrahigh-energy cosmic-ray spectrum". Physical Review D 31 (3): 564–580. doi:10.1103/PhysRevD.31.564. PMID 9955721. Bibcode1985PhRvD..31..564H. 
  18. Hill, Christopher T.; Schramm, David N.; Walker, Terry P. (1987). "Ultrahigh-Energy Cosmic Rays from Superconducting Cosmic Strings". Phys. Rev. D 36 (4): 1007–1016. doi:10.1103/physrevd.36.1007. PMID 9958264. Bibcode1987PhRvD..36.1007H. 
  19. Bhattacharjee, Pijushpani; Hill, Christopher T.; Schramm, David N. (1992). ""Grand unified theories," topological defects and ultrahigh-energy cosmic rays". Phys. Rev. Lett. 69 (4): 567–570. doi:10.1103/PhysRevLett.69.567. PMID 10046974. Bibcode1992PhRvL..69..567B. 
  20. Hill, Christopher T. (1983). "Monopolonium". Nuclear Physics B 224 (3): 469–490. doi:10.1016/0550-3213(83)90386-3. Bibcode1983NuPhB.224..469H. 
  21. Hill, Christopher T. (2015). "Axion Induced Oscillating Electric Dipole Moments". Physical Review D 224 (3): 111702. doi:10.1103/PhysRevD.91.111702. Bibcode2015PhRvD..91k1702H. 
  22. Hill, Christopher T. (2016). "Axion Induced Oscillating Electric Dipole Moment of the Electron". Physical Review D 224 (3): 025007. doi:10.1103/PhysRevD.93.025007. Bibcode2016PhRvD..93b5007H. 
  23. Ferreira, Pedro G.; Hill, Christopher T.; Ross, Graham G. (8 February 2017). "Weyl current, scale-invariant inflation, and Planck scale generation". Physical Review D 95 (4): 043507. doi:10.1103/PhysRevD.95.043507. Bibcode2017PhRvD..95d3507F. 
  24. Ferreira, Pedro G.; Hill, Christopher T.; Ross, Graham G. (2018). "Inertial Spontaneous Symmetry Breaking and Quantum Scale Invariance". Physical Review D 98 (11): 116012. doi:10.1103/PhysRevD.98.116012. Bibcode2018PhRvD..98k6012F. 
  25. Hill, Christopher T.; Ross, Graham G. (2020). "Gravitational Contact Terms and the Physical Equivalence of Weyl Transformations in Effective Field Theory". Physical Review D 102: 125014. doi:10.1103/PhysRevD.102.125014. 
  26. "APS Fellow Archive". https://www.aps.org/programs/honors/fellowships/archive-all.cfm?initial=&year=1989&unit_id=&institution=Fermi+National+Accelerator+Laboratory.  (search on year=1989 and institution=Fermi National Accelerator Laboratory)

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