

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
nearfuture 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 longsought 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 nonspecialist, 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:
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 the Higgs boson 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. I am a member of the
NonMinimalHiggs project.
Student positions:
 The Theory Group is looking for up to six new grad students
to start in September 2021.
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 midJanuary for the
following summer.)
Recent publications and preprints (students in bold type):
 H. E. Logan, S. Moretti, D. RojasCiofalo, and M. Song,
"CP violation from charged Higgs bosons in the three Higgs doublet model,"
arXiv:2012.08846 [hepph].
 D. Azevedo, P. M. Ferreira, H. E. Logan, and R. Santos,
"Vacuum structure of the Z_2 symmetric GeorgiMachacek mmodel,"
J. High Energy Phys. 03 (2021) 221
[arXiv:2012.07758 [hepph]].
 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 [hepph]].
 A. Ismail, B. Keeshan, H. E. Logan, and Y. Wu,
"A benchmark for LHC searches for lowmass custodial fiveplet scalars in the GeorgiMachacek model,"
Phys. Rev. D 103, 095010 (2021)
[arXiv:2003.05536 [hepph]].
 A. Ismail, H. E. Logan, and Y. Wu,
"Updated constraints on the GeorgiMachacek model from LHC Run 2,"
arXiv:2003.02272 [hepph].
 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 [hepph]].
 B. Keeshan, H. E. Logan and T. Pilkington,
"Custodial symmetry violation in the GeorgiMachacek model,"
Phys. Rev. D 102, 015001 (2020)
[arXiv:1807.11511 [hepph]].
 H. E. Logan and M. B. Reimer,
"Characterizing a benchmark scenario for heavy Higgs boson searches in the GeorgiMachacek model,"
Phys. Rev. D 96, 095029 (2017)
[arXiv:1709.01883 [hepph]].
 C. Degrande, K. Hartling and H. E. Logan,
"Scalar decays to gamma gamma, Z gamma, and W gamma in the
GeorgiMachacek model,"
Phys. Rev. D 96, 075013 (2017)
[arXiv:1708.08753 [hepph]].
 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 [hepph]].
 H. E. Logan and T. Pilkington,
"Large scalar multiplet dark matter in the highmass region,"
Phys. Rev. D 96, 015030 (2017)
[arXiv:1610.08835 [hepph]].
 R. Campbell, S. Godfrey, H. E. Logan and A. Poulin,
"Real singlet scalar dark matter extension of the GeorgiMachacek model,"
Phys.
Rev. D 95, 016005 (2017)
[arXiv:1610.08097 [hepph]].
 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 [hepph].
 C. Degrande, K. Hartling, H. E. Logan, A. D. Peterson and M. Zaro,
"Automatic predictions in the GeorgiMachacek model at nexttoleading order accuracy,"
Phys.
Rev. D 93, 035004 (2016)
[arXiv:1512.01243 [hepph]].
 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 [hepph]].
 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 [hepph]].
 R. Campbell, S. Godfrey, H. E. Logan, A. D. Peterson
and A. Poulin,
"Implications of the observation of dark matter selfinteractions for singlet
scalar dark matter,"
Phys.
Rev. D 92, 055031 (2015)
[arXiv:1505.01793 [hepph]].
 H. E. Logan and V. Rentala,
"All the generalized GeorgiMachacek models,"
Phys.
Rev. D 92, 075011 (2015)
[arXiv:1502.01275 [hepph]].
 H. E. Logan,
"Hiding a Higgs width enhancement from offshell gg (> h*) > ZZ measurements,"
Phys.
Rev. D 92, 075038 (2015)
[arXiv:1412.7577 [hepph]].
 K. Hartling, K. Kumar, and H. E. Logan,
"GMCALC: a calculator for the GeorgiMachacek model,"
arXiv:1412.7387 [hepph].
 K. Hartling, K. Kumar, and H. E. Logan,
"Indirect constraints on the GeorgiMachacek model and implications
for Higgs couplings,"
Phys.
Rev. D 91, 015013 (2015)
[arXiv:1410.5538 [hepph]].
 K. Hartling, K. Kumar, and H. E. Logan,
"The decoupling limit in the GeorgiMachacek model,"
Phys.
Rev. D 90, 015007 (2014)
[arXiv:1404.2640 [hepph]].
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
