A personal note to my physics friends
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I'm a professor in the
Theoretical Particle
Physics Group in
the Physics Department
at Carleton University, located
on the traditional and unceded territory of the Algonquin Nation in
Ottawa, Canada. The theory group works on a wide range of topics in
high energy physics, with a focus on topics relevant to current or
near-future particle physics experiments.
My research is on theoretical aspects of Higgs physics, which
addresses the question of the origin of mass. This topic is very
exciting these days since the discovery in summer 2012 of a new
particle consistent with being the long-sought Higgs boson of the
Standard Model. Our task now is to understand the properties of this
new particle and to determine whether it is indeed responsible for
generating the masses of other fundamental particles. This quest
could potentially shed light on a wide array of possible solutions to
the problem of mass: everything from new forces of nature, to
supersymmetry, to extra dimensions of space. This could give us a
window not only on the origin of mass, but also on the dark matter in
the universe and maybe the origin of ordinary matter as well. Data
from the Large Hadron
Collider at CERN in Geneva,
Switzerland, should allow many of these questions to be answered.
(For the non-specialist, here's a really nice
interview with Prof. Sean Carroll
in which he explains the importance of the Higgs.)
For a technical introduction to Higgs physics suitable for grad students,
see my:
and for an even more technical introduction to perturbative unitarity
techniques in Higgs physics (meant as a companion volume to my TASI
2013 lectures), see my:
- Lectures on perturbative unitarity and decoupling in Higgs physics,
arXiv:2207.01064.
My research involves studying the details of theoretical models in
order to work out their predictions for what can be seen and measured
in experiments, thereby allowing the models to be tested. Recently my
work has focused on properties of Higgs bosons in extended Higgs
sectors: in particular, the properties of charged Higgs bosons,
strategies for distinguishing different models, and the possible
connections of these models to dark matter.
Student positions:
- The Theory Group is looking for new grad students to start in September 2023.
More information is on the
Theory Group webpage.
- I usually take an undergrad summer student each year through the NSERC
USRA
program. Here's
how to apply. (Applications are normally due in mid-January for the
following summer.)
Recent publications and preprints (students in bold type):
- C. H. de Lima and H. E. Logan,
"Unavoidable Higgs coupling deviations in the Z_2-symmetric Georgi-Machacek model,"
Phys. Rev. D 106, 115020 (2022)
[arXiv:2209.08393 [hep-ph]].
- H. E. Logan, S. Moretti, D. Rojas-Ciofalo, and M. Song,
"CP violation from charged Higgs bosons in the three Higgs doublet model,"
J. High Energy Phys. 07 (2021) 158
[arXiv:2012.08846 [hep-ph]].
- D. Azevedo, P. M. Ferreira, H. E. Logan, and R. Santos,
"Vacuum structure of the Z_2 symmetric Georgi-Machacek mmodel,"
J. High Energy Phys. 03 (2021) 221
[arXiv:2012.07758 [hep-ph]].
- C. H. de Lima, B. Keeshan, H. E. Logan, and Y. Zhang,
"Probing Dark Sector CP Violation with Electric Dipole Moments and
Colliders,"
Phys. Rev. D 103, 115034 (2021)
[arXiv:2010.06441 [hep-ph]].
- A. Ismail, B. Keeshan, H. E. Logan, and Y. Wu,
"A benchmark for LHC searches for low-mass custodial fiveplet scalars in the Georgi-Machacek model,"
Phys. Rev. D 103, 095010 (2021)
[arXiv:2003.05536 [hep-ph]].
- A. Ismail, H. E. Logan, and Y. Wu,
"Updated constraints on the Georgi-Machacek model from LHC Run 2,"
arXiv:2003.02272 [hep-ph].
- H. E. Logan and Y. Wu,
"Searching for the W gamma decay of a charged Higgs boson,"
J.
High Energy Phys. 11 (2018) 121
[arXiv:1809.09127 [hep-ph]].
- B. Keeshan, H. E. Logan and T. Pilkington,
"Custodial symmetry violation in the Georgi-Machacek model,"
Phys. Rev. D 102, 015001 (2020)
[arXiv:1807.11511 [hep-ph]].
- H. E. Logan and M. B. Reimer,
"Characterizing a benchmark scenario for heavy Higgs boson searches in the Georgi-Machacek model,"
Phys. Rev. D 96, 095029 (2017)
[arXiv:1709.01883 [hep-ph]].
- C. Degrande, K. Hartling and H. E. Logan,
"Scalar decays to gamma gamma, Z gamma, and W gamma in the
Georgi-Machacek model,"
Phys. Rev. D 96, 075013 (2017)
[arXiv:1708.08753 [hep-ph]].
- M.-J. Harris and H. E. Logan,
"Constraining the scalar septet model through vector boson scattering,"
Phys. Rev. D 95, 095003 (2017)
[arXiv:1703.03832 [hep-ph]].
- H. E. Logan and T. Pilkington,
"Large scalar multiplet dark matter in the high-mass region,"
Phys. Rev. D 96, 015030 (2017)
[arXiv:1610.08835 [hep-ph]].
- R. Campbell, S. Godfrey, H. E. Logan and A. Poulin,
"Real singlet scalar dark matter extension of the Georgi-Machacek model,"
Phys.
Rev. D 95, 016005 (2017)
[arXiv:1610.08097 [hep-ph]].
- G. Bonner and H. E. Logan,
"Constraining the Higgs couplings to up and down quarks using production kinematics at the CERN Large Hadron Collider,"
arXiv:1608.04376 [hep-ph].
- C. Degrande, K. Hartling, H. E. Logan, A. D. Peterson and M. Zaro,
"Automatic predictions in the Georgi-Machacek model at next-to-leading order accuracy,"
Phys.
Rev. D 93, 035004 (2016)
[arXiv:1512.01243 [hep-ph]].
- S. Godfrey and H. E. Logan,
"Novel probe of new light Higgs bosons from bottomonium chi_{b0} decay,"
Phys.
Rev. D 93, 055014 (2016)
[arXiv:1510.04659 [hep-ph]].
- H. E. Logan, T. A. Martin and T. Pilkington,
"LHC constraints on large scalar multiplet models with a Z2 symmetry,"
Phys.
Rev. D 92, 055028 (2015)
[arXiv:1507.01887 [hep-ph]].
- R. Campbell, S. Godfrey, H. E. Logan, A. D. Peterson
and A. Poulin,
"Implications of the observation of dark matter self-interactions for singlet
scalar dark matter,"
Phys.
Rev. D 92, 055031 (2015)
[arXiv:1505.01793 [hep-ph]].
- H. E. Logan and V. Rentala,
"All the generalized Georgi-Machacek models,"
Phys.
Rev. D 92, 075011 (2015)
[arXiv:1502.01275 [hep-ph]].
- H. E. Logan,
"Hiding a Higgs width enhancement from off-shell gg (--> h*) --> ZZ measurements,"
Phys.
Rev. D 92, 075038 (2015)
[arXiv:1412.7577 [hep-ph]].
- K. Hartling, K. Kumar, and H. E. Logan,
"GMCALC: a calculator for the Georgi-Machacek model,"
arXiv:1412.7387 [hep-ph].
- K. Hartling, K. Kumar, and H. E. Logan,
"Indirect constraints on the Georgi-Machacek model and implications
for Higgs couplings,"
Phys.
Rev. D 91, 015013 (2015)
[arXiv:1410.5538 [hep-ph]].
- K. Hartling, K. Kumar, and H. E. Logan,
"The decoupling limit in the Georgi-Machacek model,"
Phys.
Rev. D 90, 015007 (2014)
[arXiv:1404.2640 [hep-ph]].
For a full list
see
my InSPIRE listing. (Note: authors are listed in alphabetical
order in my field.)
Quick links to working group reports:
Biography
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