Investigating Higgs self-interaction through di-Higgs plus jet production Kangyu Chai1 2Jiang-Hao Yu3 4 5 6 7yand Hao Zhang1 2 5z 1Theoretical Physics Division Institute of High Energy Physics

2025-05-03 0 0 621.18KB 9 页 10玖币
侵权投诉
Investigating Higgs self-interaction through di-Higgs plus jet production
Kangyu Chai,1, 2, Jiang-Hao Yu,3, 4, 5, 6, 7, and Hao Zhang1, 2, 5,
1Theoretical Physics Division, Institute of High Energy Physics,
Chinese Academy of Sciences, Beijing 100049, China
2School of Physics, University of Chinese Academy of Science, Beijing 100049, China
3CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics,
Chinese Academy of Sciences, Beijing 100190, China
4School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
5Center for High Energy Physics, Peking University, Beijing 100871, China
6School of Fundamental Physics and Mathematical Sciences,
Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
7International Centre for Theoretical Physics Asia-Pacific, Beijing/Hangzhou, China
(Dated: October 28, 2022)
The Higgs self coupling measurement is quite essential for determining the shape of the Higgs
potential and nature of the Higgs boson. We propose the di-Higgs plus jet final states at hadron
colliders to increase the discovery sensitivity of the Higgs self coupling at the low invariant mass
region. Our simulation indicates that the allowed region of the Higgs self coupling would be further
narrowed from [1.5,6.7] from the most recent ATLAS report down to [0.5,1.7]. Furthermore, we
find negative Higgs self couplings would be disfavored beyond 2σconfidence level at a future 100 TeV
collider with the help of this signal.
I. INTRODUCTION
The discovery of the Higgs boson in 2012 [1, 2]
represents one milestone of modern particle physics.
It provides the evidence that the observed Higgs
boson is the one predicted by the Standard Model
(SM). While the SM parameters have essentially been
measured to a very high precision level, the Higgs
self couplings, important for electroweak symmetry
breaking and understanding its connection to other
fundamental questions like electroweak baryogenesis [3],
have not been measured directly yet. More importantly,
depending on the nature of the Higgs boson, such
as fundamental, pseudo-Goldstone, pseudo-Dilaton, or
partially composite, the shape of the Higgs potential
could be quite different from the SM one [4]. Indeed,
a wide range of new physics (NP) models beyond
the SM predict modified Higgs potentials that lead
to O(1) corrections to the Higgs self couplings, the
Coleman-Weinberg [5–7] and the tadpole-induced [8, 9]
Higgs scenarios for example. Therefore, a precision
measurement of the Higgs self couplings would provide
an important benchmark for model identification and
deepen our understanding on electroweak symmetry
breaking (EWSB).
Experimentally, the Higgs self couplings could be
measured directly from Higgs pair production or Higgs
associated production. Due to their lower cross sections
for the latter, in this work, we focus specifically on
the former that is dominated by gluon-gluon fusion
Electronic address: chaikangyu@ihep.ac.cn
Electronic address: jhyu@itp.ac.cn
Electronic address: zhanghao@ihep.ac.cn
(ggF) at hadron colliders that has been studied in detail
earlier [10–12].1However, due to a strong cancellation
near the kinematical threshold, the cross sections for
Higgs pair production is highly suppressed – At a 13 TeV
pp collider, the ggF cross section for the Higgs pair
production is calculated at next-to-next-to leading order
in finite top-quark mass approximation, and the result
is 31.02+2.2%
5.0%(scale)+4%
18%(mtop)±3.0%(αs+ PDF) fb [17–
20]. Here, “scale” stands for the uncertainty from finite
order quantum chromodynamics calculation, mtop” that
from the top-quark mass scheme [20, 21], and “αs+PDF”
that from the strong coupling constant and the parton
distribution functions. As a consequence, the Higgs self
couplings are only very loosely bounded [22], let alone
their precision determination.
Nevertheless, it is worth pointing out that current
experimental searches mainly focus on the high di-Higgs
invariant mass region, while it is perhaps universally
recognized that the it is the low mass region that is most
sensitive to NP. This motivates the study of Higgs self
couplings in the low mass region in this work. To increase
the significance of the di-Higgs signal in this region, we
consider instead Higgs pair production through ggF with
an extra hard jet in the final state, i.e., pp hh+jet+X,
with Xany other particles in the final state that we
are not interested in. Similar to the pure di-Higgs
production channel, we consider the bbγγ decay channel
of the Higgs pair for its cleanness and the unambiguity
in reconstructing the two Higgs particles.
1Lepton colliders could also measure Higgs self couplings directly,
see, for example, Refs. [13–16]. We focus on hadron colliders in
this work given the foreseen high-luminosity/energy era of the
Large Hadron Collider (LHC) in the near future.
arXiv:2210.14929v1 [hep-ph] 26 Oct 2022
2
The rest of the paper is organized as follows: In
section II, we set up the framework used in this work,
and briefly summarize previous searches in di-Higgs
production. We then detail our strategy for pp
hh+jet+Xsearches in section III. Results from detector-
level simulation for this channel are then presented in
section IV, and we conclude in section V.
II. HIGGS NATURE DETERMINATION VIA
HIGGS SELF INTERACTIONS
In the effective field theory (EFT) framework, new
physics effect in the Higgs sector could be described using
Higgs EFT (HEFT) and standard model EFT (SMEFT)
in the broken and unbroken phase of electroweak
symmetry, respectively. Although SMEFT is the
most popular EFT scenario, its validity relies on the
assumptions that new physics should decouple at low
energy scale. On the other hand, the HEFT would
describe the Higgs potential in the broken phase and thus
describe the nature of the Higgs and the Higgs couplings
in a more general way.
In the HEFT scenario [23–30], the electroweak gauge
symmetry is broken down to the U(1)em and the global
SU (2)L×SU (2)R/SU (2)Vsymmetry in the Higgs sector
is non-linearly realized. Treating the Higgs boson has an
electroweak singlet, the HEFT Lagrangian at the leading
order reads
L=v2
4Tr DµUDµU1+2ah
v+bh2
v2+···+ (1)
1
2(µh)21
2m2
hh2κλm2
h
2vh3κhm2
h
8v2h4+···
which parametrize the Higgs potential in the polynomial
form and does not depends on the decoupling behavior.
Depending on the nature of the Higgs boson, the
Higgs potential could be different from the SM form as
parameterized by κλ,h.
In the SMEFT scenario [31–41], the Higgs potential
can be expressed as
Vh⊃ −µ2HH+λHH2+c6
Λ2λHH3+··· (2)
where Λ is the UV cutoff, c6is some dimensionless
Wilson coefficient, and “···” represents some higher
dimensional operators of the SMEFT. The triple and
quartic Higgs couplings can then be easily matched to
above parameters after electroweak symmetry breaking
upon substituting Hfor (0, v +h)T/2, leading to [4]
Vh1
22λv2+3c6λv4
Λ2h2+λv 1 + 5c6v2
2h3
+1
4λ1 + 15c6v2
2h4+···
where we have applied the minimization condition µ2=
λv2+ 3c6λv4/(4Λ2) to obtain the expression above and
TABLE I: Higgs self couplings κλand κhin different
cases. Here, “MCH5+5” means the minimal composite
Higgs model [42, 43], “CTH8+1 ” the composite twin Higgs
model [44–46], and “CW” the Coleman-Weinberg Higgs
scenario [5–7]. The first (second) subscript of the model name
represents the fundamental representation of the left-(right-
)handed top quark under the global symmetry, which is SO(5)
and SO(8) for “MCH5+5” and “CTH8+1”, respectively. In the
CW Higgs scenario, numbers in parentheses are results up to
the two-loop order from Refs.[5, 6].
Higgs self couplings κλκh
SM 1 1
SMEFT (with O6) 1 + c6v2
Λ21 + 6c6v2
Λ2
MCH5+5 13
2ξ125
3ξ
CTH8+1 13
2ξ125
3ξ
CW Higgs (doublet) 5
3(1.75) 11
3(4.43)
CW Higgs (singlets) 5
3(1.91) 11
3(4.10)
Tadpole-induced Higgs '0'0
discarded terms that are not interested for the study in
this work. Matching between the HEFT and the SMEFT
operators, the Higgs mass and the κ’s are defined as, up
to O(1/Λ2),
m2
h2λv2+3c6λv4
Λ2, κλ1 + c6v2
Λ2, κh1 + 6c6v2
Λ2.(3)
Note that one reproduces SM tree-level results upon
setting c6= 0. We comment on that (HH)2(HH) and
(HDµH)(HDµH) would also contribute to shifting the
Higgs mass and the Higgs self couplings from the kinetic
Lagrangian, we leave out these operators in our analysis since
they are highly constrained by electroweak precision physics
and/or hV V (V=W±, Z) couplings [4].
Depending on the nature of the Higgs boson, the Higgs
boson could be fundamental, pseudo-Goldstone, pseudo-
Dilaton, or partially composite due to strong dynamics
condensation [4]. For a fundamental Higgs boson, such as
the SM Higgs boson and its scalar/gauge extensions, and
supersymmetric models, the form of the Higgs potential
is polynomial on the Higgs doublet. In this case, there
usually exist additional scalars mixed with the SM Higgs
boson, thus modifying the SM Higgs self couplings with some
enhancement. In contrast, if the Higgs boson is pseudo-
Goldstone due to the vacuum misalignment, the curvature of
the Higgs field would cause the Higgs couplings to be always
smaller than their SM values. On the other hand, if the Higgs
boson is a pseudo-dilaton, the Higgs potential would be of
purely the Coleman-Weinberg type and thus the Higgs self-
couplings would be larger than the SM ones. Finally, if the
symmetry breaking is partially induced by condensation, it is
possible to have the tadpole-induced symmetry breaking and
thus the Higgs self couplings are nearly zero. We summarize
the Higgs self couplings in different scenarios discussed above
in Table I.
Therefore, measuring the Higgs self couplings could
possibly unveil the pattern of EWSB, which in turn helps
determine the nature of the Higgs boson. In this context,
摘要:

InvestigatingHiggsself-interactionthroughdi-HiggsplusjetproductionKangyuChai,1,2,Jiang-HaoYu,3,4,5,6,7,yandHaoZhang1,2,5,z1TheoreticalPhysicsDivision,InstituteofHighEnergyPhysics,ChineseAcademyofSciences,Beijing100049,China2SchoolofPhysics,UniversityofChineseAcademyofScience,Beijing100049,China3CAS...

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Investigating Higgs self-interaction through di-Higgs plus jet production Kangyu Chai1 2Jiang-Hao Yu3 4 5 6 7yand Hao Zhang1 2 5z 1Theoretical Physics Division Institute of High Energy Physics.pdf

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