944 research outputs found
Optimizing Higgs factories by modifying the recoil mass
Full text linkIt is difficult to measure the -fusion Higgs production process () at a lepton collider with a center of mass energy of
240-250 GeV due to its small rate and the large background from the
Higgsstrahlung process with an invisible (). We construct a modified recoil mass variable, , defined using only the 3-momentum of the reconstructed Higgs
particle, and show that it can better separate the -fusion and
Higgsstrahlung events than the original recoil mass variable .
Consequently, the variable can be used to improve the
overall precisions of the extracted Higgs couplings, in both the conventional
framework and the effective-field-theory framework. We also explore the
application of the variable in the inclusive cross section
measurements of the Higgsstrahlung process, while a quantitive analysis is left
for future studies.Comment: 25 pages, 8 figure
Higgs mass from compositeness at a multi-TeV scale
Full text linkWithin composite Higgs models based on the top seesaw mechanism, we show that
the Higgs field can arise as the pseudo Nambu-Goldstone boson of the broken
U(3)_L chiral symmetry associated with a vector-like quark and the t-b doublet.
As a result, the lightest CP-even neutral state of the composite scalar sector
is lighter than the top quark, and can be identified as the newly discovered
Higgs boson. Constraints on weak isospin violation push the chiral symmetry
breaking scale above a few TeV, implying that other composite scalars are
probably too heavy to be probed at the LHC, but may be within reach at a future
hadron collider with center-of-mass energy of about 100 TeV.Comment: 30 pages. v2: discussion of T parameter expanded; references added.
To be published in JHE
Beyond Higgs Couplings: Probing the Higgs with Angular Observables at Future Colliders
Full text linkWe study angular observables in the channel at future circular colliders such as CEPC
and FCC-ee. Taking into account the impact of realistic cut acceptance and
detector effects, we forecast the precision of six angular asymmetries at CEPC
(FCC-ee) with center-of-mass energy 240 GeV and 5 (30) integrated luminosity. We then determine the projected sensitivity to
a range of operators relevant for the Higgs-strahlung process in the
dimension-6 Higgs EFT. Our results show that angular observables provide
complementary sensitivity to rate measurements when constraining various tensor
structures arising from new physics. We further find that angular asymmetries
provide a novel means of both probing BSM corrections to the
coupling and constraining the "blind spot" in indirect limits on supersymmetric
scalar top partners.Comment: 28 pages, 9 figures. v2: references added, matches published version
in JHE
The leptonic future of the Higgs
Full text linkPrecision study of electroweak symmetry breaking strongly motivates the
construction of a lepton collider with center-of-mass energy of at least 240
GeV. Besides Higgsstrahlung (), such a collider would measure
weak boson pair production () with an astonishing precision. The
weak-boson-fusion production process () provides an
increasingly powerful handle at higher center-of-mass energies. High energies
also benefit the associated top-Higgs production () that is
crucial to constrain directly the top Yukawa coupling. The impact and
complementarity of differential measurements, at different center-of-mass
energies and for several beam polarization configurations, are studied in a
global effective-field-theory framework. We define a "global determinant
parameter" (GDP) which characterizes the overall strengthening of constraints
independently of the choice of operator basis. The reach of the CEPC, CLIC,
FCC-ee, and ILC designs is assessed.Comment: 55 pages, lots of figures, v2: references added, minor corrections,
extended discussions on quadratic EFT contributions and beam polarization
effects, matches published version in JHE
- β¦
