The study of the extended Higgs boson sector within 2HDM model
Consideration of the latest experimental data on the searches for extended sector of Higgs bosons produced at the LHC at a center-of-mass energy of 13TeV, allows for computer modeling of the properties of supersymmetric particles within 2HDM model. The experimental restrictions on model parameters a...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
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irk-123456789-1360692018-06-16T03:03:51Z The study of the extended Higgs boson sector within 2HDM model Obikhod, T.V. Petrenko, E.A. Ядерная физика и элементарные частицы Consideration of the latest experimental data on the searches for extended sector of Higgs bosons produced at the LHC at a center-of-mass energy of 13TeV, allows for computer modeling of the properties of supersymmetric particles within 2HDM model. The experimental restrictions on model parameters accounted in FeynHiggs code that is implemented in SusHi program, gave us the possibility to calculate the cross sections and branching fractions for three mechanisms of production and decay of Higgs bosons: 1) pp→H→ττ, 2) pp→A →Zh→llbb, 3) pp→H→ hh→bbττ at a center-of-mass energy of 14TeV. The considered computer modelling make it possible to draw conclusions about the need to take into account the b-associated production process of Higgs bosons for fermionic decay channel at large values of tanβ. Differential cross sections with respect to the Higgs transverse momentum pₜ and pseudorapidity η are calculated and the peculiarities of the kinematics of the Higgs boson decay products are recognized. Облiк останнiх експериментальних даних з пошуку розширеного сектора бозонiв Хiггса, отриманих на БАК при енергiї протон-протонного зiткнення 13 ТеВ, дозволяє провести комп’ютерне моделювання властивостей суперсиметричних частинок у рамках 2HDM-моделi. Експериментально отриманi обмеження на параметри моделi, якi врахованi в iмплементованому в SusHi кодi FeynHiggs, дали нам можливiсть порахувати перерiзи, ширини розпадiв для трьох механiзмiв народження i розпаду бозонiв Хiггса: 1) pp→H→ττ, 2) pp→A →Zh→llbb, 3) pp→H→ hh→bbττ при енергiї в системi центра мас 14 ТеВ. Розглянутi розрахунки дають можливiсть зробити висновки про необхiднiсть врахування b-асоцiйованого процесу народження бозонiв Хiггса для фермiонного каналу розпаду при великих значеннях параметра tanβ. Отримано розподiли диференцiальних перерiзiв по поперечному iмпульсу pₜ i по псевдошвидкостi η, i виявлено особливостi кiнематики продуктiв розпаду бозонiв Хiггса. Учет последних экспериментальных данных по поиску расширенного сектора бозонов Хиггса, полученных на БАК при энергии протон-протонного взаимодействия 13 ТэВ, позволяет провести компьютерное моделирование свойств суперсимметричных частиц в рамках 2HDM-модели. Экспериментально полученные ограничения на параметры модели, учтенные в имплементированном в SusHi коде FeynHiggs, дали нам возможность посчитать величины сечений, ширины распадов для трех механизмов рождения и распада бозонов Хиггса: 1) pp→H→ττ, 2) pp→A →Zh→llbb, 3) pp→H→ hh→bbττ при энергии в системе центра масс 14 ТэВ. Рассмотренные расчеты дают возможность сделать выводы о необходимости учета b-ассоциированного процесса рождения бозонов Хиггса для фермионного канала распада при больших значениях параметра tanβ. Получены распределения дифференциальных сечений по поперечному импульсу pₜ и по псевдобыстроте η, и выявлены особенности кинематики продуктов распада бозонов Хиггса. 2017 Article The study of the extended Higgs boson sector within 2HDM model / T.V. Obikhod, E.A. Petrenko // Вопросы атомной науки и техники. — 2017. — № 3. — С. 3-10. — Бібліогр.: 12 назв. — англ. 1562-6016 PACS: 11.25.-w, 12.60.Jv, 02.10.Ws http://dspace.nbuv.gov.ua/handle/123456789/136069 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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English |
| topic |
Ядерная физика и элементарные частицы Ядерная физика и элементарные частицы |
| spellingShingle |
Ядерная физика и элементарные частицы Ядерная физика и элементарные частицы Obikhod, T.V. Petrenko, E.A. The study of the extended Higgs boson sector within 2HDM model Вопросы атомной науки и техники |
| description |
Consideration of the latest experimental data on the searches for extended sector of Higgs bosons produced at the LHC at a center-of-mass energy of 13TeV, allows for computer modeling of the properties of supersymmetric particles within 2HDM model. The experimental restrictions on model parameters accounted in FeynHiggs code that is implemented in SusHi program, gave us the possibility to calculate the cross sections and branching fractions for three mechanisms of production and decay of Higgs bosons: 1) pp→H→ττ, 2) pp→A →Zh→llbb, 3) pp→H→ hh→bbττ at a center-of-mass energy of 14TeV. The considered computer modelling make it possible to draw conclusions about the need to take into account the b-associated production process of Higgs bosons for fermionic decay channel at large values of tanβ. Differential cross sections with respect to the Higgs transverse momentum pₜ and pseudorapidity η are calculated and the peculiarities of the kinematics of the Higgs boson decay products are recognized. |
| format |
Article |
| author |
Obikhod, T.V. Petrenko, E.A. |
| author_facet |
Obikhod, T.V. Petrenko, E.A. |
| author_sort |
Obikhod, T.V. |
| title |
The study of the extended Higgs boson sector within 2HDM model |
| title_short |
The study of the extended Higgs boson sector within 2HDM model |
| title_full |
The study of the extended Higgs boson sector within 2HDM model |
| title_fullStr |
The study of the extended Higgs boson sector within 2HDM model |
| title_full_unstemmed |
The study of the extended Higgs boson sector within 2HDM model |
| title_sort |
study of the extended higgs boson sector within 2hdm model |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2017 |
| topic_facet |
Ядерная физика и элементарные частицы |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/136069 |
| citation_txt |
The study of the extended Higgs boson sector within 2HDM model / T.V. Obikhod, E.A. Petrenko // Вопросы атомной науки и техники. — 2017. — № 3. — С. 3-10. — Бібліогр.: 12 назв. — англ. |
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Вопросы атомной науки и техники |
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2025-07-09T21:22:50Z |
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| fulltext |
NUCLEAR PHYSICS AND ELEMENTARY PARTICLES
THE STUDY OF THE EXTENDED HIGGS BOSON SECTOR
WITHIN 2HDM MODEL
T.V.Obikhod, E.A.Petrenko ∗
Institute for Nuclear Research National Academy of Sciences of Ukraine, 03068, Kiev, Ukraine
(Received March 10, 2017)
Consideration of the latest experimental data on the searches for extended sector of Higgs bosons produced at the
LHC at a center-of-mass energy of 13TeV, allows for computer modeling of the properties of supersymmetric particles
within 2HDM model. The experimental restrictions on model parameters accounted in FeynHiggs code that is imple-
mented in SusHi program, gave us the possibility to calculate the cross sections and branching fractions for three mech-
anisms of production and decay of Higgs bosons: 1) pp→ H → ττ , 2) pp→ A → Zh → llbb, 3) pp→ H → hh → bbττ
at a center-of-mass energy of 14TeV. The considered computer modelling make it possible to draw conclusions about
the need to take into account the b-associated production process of Higgs bosons for fermionic decay channel at large
values of tanβ. Differential cross sections with respect to the Higgs transverse momentum pt and pseudorapidity η
are calculated and the peculiarities of the kinematics of the Higgs boson decay products are recognized.
PACS: 11.25.-w, 12.60.Jv, 02.10.Ws
1. INTRODUCTION
The Higgs boson, which appears in the models of the
spontaneous breaking of electroweak symmetry and
is responsible for the occurrence of the masses of el-
ementary particles was discovered on July 4, 2012 at
the LHC [1]. This particle was observed in pp col-
lisions, mainly as a result of the gluon-gluon fusion,
and its search is performed in almost all possible de-
cay channels: W and Z bosons (WW and ZZ), bottom
quarks (bb), τ and µ leptons (ττ, µµ), photons (γγ).
Search for the Higgs boson is based on the com-
parison of experimental measurements with theoreti-
cal predictions of the Standard Model (SM). The de-
tailed study of the production and decay modes of the
new particle with mass of 125...126 GeV at the LHC
indicates that the new particle is indeed compatible
with the SM Higgs boson. Nevertheless, many sce-
narios of physics beyond SM include a SM-like Higgs
boson as part of an extended sector of scalar parti-
cles. In any case, searches for new Higgs bosons are
connected with the measurements of the properties
of the new particles of an extended sector.
In this aspect, it is necessary to pay attention to
the problem of the radiative corrections to the mass
of the Higgs boson, the solution of which is associ-
ated with the introduction of new particle, so-called
superparticle presented in Fig.1
Fig.1. Presentation of hierarchy problem solution
After mass renormalization between fermionic quark
loop and scalar squark loop, the Higgs boson
quadratic mass is limited
∆m2
H =
λ2
f
8π2
[
6m2
f ln
Λ
mf
− 2m2
S ln
Λ
mS
]
,
where mf and mS are masses of fermion and its su-
perparticle, λf is Yukawa coupling, Λ is the scale up
to which the SM is valid.
The limitation of SM is illustrated through the
renormalization-group behavior of Higgs self-coupling
λ. It depends on the numerical values of the SM pa-
rameters and defines the Landau pole to the scale
of 1019 GeV. This means that there must be a
new physics at energies that are significantly lower
the Planck scale [2]. Such behavior of self-coupling
constant which depends also on other parameters
(masses of the top quark, Mt, of Z boson, MZ , of the
Higgs boson, Mh, and on the strong coupling con-
stant, αs)
λ(MPl) = −0.0143− 0.0066
(
Mt
GeV
− 173.34
)
+
+0.0018
αs(MZ)− 0.1184
0.0007
+ 0.0029
(
Mh
GeV− 125.15
)
creates the problem of electroweak vacuum instabil-
ity.
The fact of possible existence of new physics at
the TeV scale can be studied in deviations of the
Higgs self-coupling constant from SM in the pro-
cess of Higgs boson formation and decay. The signal
∗Corresponding author E-mail address: obikhod@kinr.kiev.ua
ISSN 1562-6016. PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY, 2017, N3(109).
Series: Nuclear Physics Investigations (68), p.3-10.
3
strength µ for the production µi and decay µf mode
of Higgs boson i → H → f is defined as
µi =
σi
(σi)SM
and µf =
Bf
(Bf )SM
,
where σi (i = ggF (Gluon fusion), VBF
(Vector boson fusion), WH and ZH (Higgs
Strahlung), ttH (Top fusion)) and Bf (f =
ZZ, WW, γγ, ττ, bb, µµ) are respectively the
production cross sections and the decay branching
fractions for Higgs boson. The combined results of
the ATLAS and CMS collaborations of Higgs boson
production processes µggF , µV BF , µWH , µZH , µttH
and decay signal strengths µγγ , µZZ , µWW , µττ , µbb
for the combined
√
7 and
√
8 TeV data are presented
in Fig.2.
Fig.2. Production signal strengths (upper figure)and
decay signal strengths (lower figure) for the com-
bination of ATLAS and CMS Collaborations from [3]
The results of experimental measurements show de-
viations from the SM.
Thus, the existance of Landau pole, the problem
of electroweak vacuum instability as well as the ex-
perimental data on the production and decay sig-
nal strengths of Higgs boson, tiny Higgs mass pro-
tected from quantum corrections, prove the necessity
of searches for new physics beyond the SM.
One of the models of beyond the SM physics is the
two-Higgs doublet (2HDM) model [4]. This model
provides a solution to the hierarchy problem and pre-
dicts five Higgs bosons: two neutral CP-even Higgs
bosons, h,H , one neutral CP-odd Higgs, A and two
charged Higgs bosons, H±. Higgs sector of this model
can be represented by two free parameters: the mass
of the pseudoscalar Higgs boson, MA, and the ratio
of the vacuum expectation values of the two Higgs
doublets of Higgs sector, tanβ.
The searches for evidence of beyond SM Higgs
bosons is an integral part of Run II at the LHC with
the center-of-mass energy of 13 TeV. Experimental
searches for Higgs sector were performed at the LHC
(CMS) [5] according to the following decay channels,
presented in Fig.3
Fig.3. Decays of the Higgs boson via fermionic
channel (left) and bosonic channel (right)
In this paper we will consider the following decay
channels of beyond SM Higgs bosons:
1) via fermionic decays
• H → ττ
2) via bosonic decays
• A → Zh
• H → hh .
With the help of SusHi code we will study the prop-
erties of beyond SM Higgs bosons at 14 TeV center-
of-mass energies.
2. HIGGS BOSON PRODUCTION CROSS
SECTION IN pp-COLLISIONS
As the main production mechanism of Higgs bosons
is gluon fusion pp → gg → H, lowest order of the
parton cross section σLO(gg → H) is expressed by
the gluonic width of the Higgs boson ΓLO(H → gg)
[6]
σLO(gg → H) =
8π2
m5
H
ΓLO(H → gg)δ(ŝ−m2
H) .
The lowest-order proton-proton cross section
σLO(pp → H) can be defined by gluon luminosity
4
as
σLO(pp → H) = σ0τH
dLgg
dτH
,
where s is the invariant pp collider energy squared,
τH =
m2
H
s and
σ0 =
GFα
2
s(µ
2)
288
√
2π
∣∣∣∣∣34∑
Q
AQ(τQ)
∣∣∣∣∣
2
,
where GF is Fermi coupling constant, αs is strong
coupling, AQ denotes the quark amplitude and µ is
the renormalization point and defines the scale pa-
rameter of αs.
The pp cross-section of Higgs bosons ϕ ∈
{h,H,A} formation at the NLO (next-to-leading or-
der) QCD corrections, is written as follows:
σ(pp → H +X) = σ0
[
1 + C
αs
π
]
τH
dLgg
dτH
+
+∆σgg +∆σgq +∆σqq ,
where C arises from two-loop corrections of partonic
cross-section, the quantities ∆σgg, ∆σgq and ∆σqq of
the partonic cross section arise from gg, gq and qq
scattering.
The coupling of the Higgs ϕ to the bottom quarks
in supersymmetric theory can be significant value
comparable with the gluon-gluon fusion that is as-
sociated with large values of tanβ. Accounting for
the large tanβ values leads to the associated Higgs
production (bb)ϕ+X illustrated in Fig.4.
Fig.4. Leading order diagrams of the a) gluon
fusion and b-associated Higgs production in the
b) four-flavour and c) five-flavour scheme from [5]
With the help of SusHi code (1.6.1 version) [7], we
carried out calculations of Higgs boson H cross-
section formation that include NNLO QCD contri-
butions to LO quantities. This program also allows to
calculate the differential cross sections of these pro-
cesses with respect to the Higgs transverse momen-
tum pt and (pseudo-)rapidity y(η) through NNLO
QCD contributions [8].
The branching ratio of the Higgs boson for differ-
ent benchmark scenarios, as well as the Yukawa cou-
pling constants of the Higgs boson that are needed
for the calculation of cross-sections were modelled
using FeynHiggs code (version 2.12.0) [9]. Minimal
Supersymmetric Standard Model (MSSM) param-
eters were determined from the experimental data
according to [10], shown in Fig.5
Fig.5. Restrictions on the parameters of the MSSM
model from [10]
From Fig.5, it can be concluded that the decays of
the Higgs boson via fermionic channel are sensitive
to large tangents, while the decays of the Higgs bo-
son via bosonic channel are sensitive to the range of
small tangents. This fact will be used by us during
the cross section and branching ratio calculations
of Higgs boson for an optimal agreement with the
experimental data at low energies and for the best
predictions at energies of 14 TeV at the LHC.
3. CROSS SECTION AND BRANCHING
FRACTION CALCULATIONS
3.1. The searches for a neutral Higgs boson,
H via fermion decay, H → ττ
Experimental data on the searches for the Higgs bo-
son in the mass range 90...1000 GeV via decay chan-
nel A\H\h → ττ are presented in [5]. The accuracy
of the data calculations is based on the searches for
three neutral Higgs bosons of MSSM model through
the reconstruction of the invariant mass of two τ
mesons with their subsequent decays into muons,
electrons and hadrons, µµ, eµ, µτh, eτh, τhτh. To in-
5
crease the accuracy of data analysis was measured
cross section of b quark associated Higgs boson pro-
duction, as an increase in constant coupling with τ
leptons is observed for this process of Higgs boson
creation. This channel of Higgs decay to ττ final
state is perfect one to test the viability of MSSM
model. Experimental data on the search for the
Higgs boson for the gluon fusion process (ggϕ) and
the b-associated production process (bbϕ) recorded
by the CMS detector at 13 TeV centre-of-mass en-
ergy in 2015 are presented in Fig.6
Fig.6. σ(gg(bb) → ϕ)B(ϕ → ττ) for a) the gluon
fusion process (ggϕ) and b) the b-associated produc-
tion process (bbϕ) from [5]
Using the experimental data for the restriction of
the numerical values of MSSM parameters, shown
in Fig.6, with the help of computer program SusHi,
we have calculated σ(pp → H)B(H → ττ(bb)) for
the gluon-gluon fusion (ggϕ) and b-associated pro-
duction process (bbϕ). From the perspective of the
searches for new physics at the LHC at an energy of
14 TeV, we have carried out calculations for energy
of proton-proton collisions of 14 TeV, via two most
probable decay channels of the Higgs boson H → ττ
and H → bb for the gluon-gluon or b-associated pro-
cess of the Higgs boson formation. The results of our
calculations are presented in Fig.7
Fig.7. σ(pp → H)B(H → ττ(bb)) for the gluon-
gluon fusion and b-associated production process in
the range of Higgs mass MH = 300...1000 GeV with
tanβ=17 and energy 14 TeV for two decay channels
of the Higgs boson, H → ττ (up) and H → bb (down)
From Fig.7 it can be seen the increase (by one order
of magnitude) of σ(ppH)B(H → bb) (pb) compared
with the value σ(ppH)B(H → ττ) that emphasizes
the importance of accounting of other neutral Higgs
boson decay channels at the LHC, in particular,
H → bb. In addition, we see a significant predom-
inance of (bbϕ) Higgs production process compared
with the process (ggϕ) that confirms the theoretical
predictions of the prevalence of this process due to
increase of Higgs boson Yukawa coupling constant
for large values of tanβ.
To study the kinematics of the processes, we have
calculated differential cross sections with respect to
the Higgs transverse momentum pt and pseudorapid-
ity, η at 14 TeV, that are presented in Fig.8
6
Fig.8. Differential cross sections with respect to the
Higgs boson H transverse momentum pt, (up) and
pseudorapidity, η (down) at the energy of 14 TeV
From Fig.8 is seen that differential cross section
smoothly decreases for ggh process. The character
of the differential cross section with respect to the
pseudorapidity indicates that the process of Higgs
boson decay is accompanied by the direction of de-
cay products that are perpendicular to the axis of
the of the proton-proton collisions. This process is
also characterized by a large value of the differen-
tial cross section in the region of pseudorapidity,
η=1...2.2, that corresponds to the angles relative to
the collision axis of ∼ 500...100.
3.2. The searches for a pseudoscalar boson, A
via dibozon decay, A → Zh
Experimental data on the searches for a pseudoscalar
boson A in the mass range of 200...600 GeV decay-
ing into a Z boson and the SM-like Higgs boson h,
where h boson decays into a pair bb and Z boson
decays into a pair of oppositely-charged electrons
or muons, were presented in [11]. The data from
proton-proton collisions at a center-of-mass energy
8 TeV collected with the CMS detector correspond
to an integrated luminosity of 19.7 fb−1. A boson is
produced via the gluon-gluon fusion and its branch-
ing fraction into Zh is relatively large compared to
other channels. Furthermore, this channel is selected
because of the lightness of detection of Z and h decay
products, Z → ll and h → bb. Branching fractions
for these decay channels are large values all over pa-
rameter space of 2HDM model. The upper limit on
the σAB(A → Zh → llbb) , in the mass range of A
boson MA = 200-600 GeV is presented in Fig.9
Fig.9. Observed and expected 95% CL upper limit
on σAB(A → Zh → llbb) as a function of MA from
[11]
Since in this mass range exists a peak with a local
significance of 2.6σ or a global 1.1σ significance, it
would be interesting to check its presence at higher
energies and luminosities. With the help of the pro-
gram SusHi we have calculated σAB(A → Zh → llbb)
in the mass range MA = 300...1000 GeV with tanβ =
2. The results of our calculations at a center-of-mass
energy of 8 TeV and at the projected at the LHC
energies of 14 TeV are presented in Fig.10
Fig.10. σAB(A → Zh → llbb) as a function of
MA at a center-of-mass energy of 8TeV (up) and of
14TeV (down)
From Fig.14 is seen an increase (by one order of mag-
7
nitude) of the value σAB(A → Zh → llbb) at MA
= 1000 GeV, that allows us to assume optimistically
the possible discovery of a pseudoscalar boson, A at
higher energies and luminosities at the LHC. In addi-
tion, we see the predominance of A boson production
through gluon-gluon fusion, that emphasizes the cor-
rectness of the theoretical predictions with respect to
the substantial Higgs interaction with the b quarks
only at high tanβ.
The calculations of differential cross sections for
pseudoscalar boson with respect to the transverse
momentum pt and pseudorapidity η at a center-of-
mass energy of 14 TeV are presented in Fig. 11
Fig.11. Differential cross sections for pseudoscalar
boson, A with respect to the transverse momentum
pt (up) and pseudorapidity η (down) at a center-of-
mass energy of 14 TeV
It should be noted that the differential cross sec-
tion with respect to the transverse momentum pt,
smoothly decreases for ggh process and is maximal
for small values of transverse momentum. The char-
acter of the differential cross section with respect
to the pseudorapidity indicates that the process of
Higgs boson decay does not have a preferred di-
rection perpendicular to the proton-proton collision
axis, that emphasizes the importance of searches for
the Higgs boson A in all directions with respect to
the collision axis. From Fig.11 is seen the significant
predominance of the value of the differential cross sec-
tions with respect to the pseudorapidity for process
A → Zh → llbb compared to the data for H → ττ)
process of the Higgs boson formation, presented in
Fig.8.
3.3. The searches for a heavy scalar boson, H
via dibozon decay, H → hh
Due to the large amount of data on decay chan-
nels, there was selected the decay channel, H →
hh(bbττ), predicted in the MSSM model. We have
performed calculations of cross sections of Higgs bo-
son formation using experimental data with three fi-
nal states, eτh, µτh, τhτh, where τh – a τ lepton de-
caying into hadrons [12]. Parameter space is selected
for largest cross section values and the range of MA
is selected with respect to recent experimental data,
presented in Fig.12.
Fig.12. The upper limit on σ(pp → H)×BR(H →
hh → bbττ) as the function of mH from [12]
In the experiment was studied the resonant Higgs
boson production via the process pp → H → hh →
bbττ , where H is the CP-even Higgs boson of un-
known mass. The branching ratio, H → hh can be
large for small values of tanβ caused by the experi-
mentally measured value of Higgs boson mass, mh ≃
125 GeV. The searches for the final state bbττ are car-
ried out taking into account the most probable decay
channels of τ leptons: eτh, µτh, τhτh. Fig.12 presents
the upper limit on the σ(pp → H)×BR(H → hh →
bbττ) for the combination of the three channels as a
function of the resonance mass mH .
Using the experimental data presented in Fig.12,
with the help of the computer program SusHi, we
calculated σ(pp → H) × BR(H → hh → bbττ) for
the gluon-gluon fusion (ggϕ) and b-associated pro-
duction process (bbϕ) at a centre-of-mass energy of
14 TeV and tanβ = 2 in the mass range MH = 300...
1000 GeV, Fig.13
Fig.13. σ(pp → H) × BR(H → hh → bbττ)
for the gluon-gluon fusion (ggϕ) and b-associated
production process (bbϕ) at a centre-of-mass energy
of 14 TeV at the LHC
In addition, it should be noted the predominance of
the process of the gluon-gluon fusion of the Higgs
8
boson production, compared with b-associated pro-
duction process in the region of small values of tanβ
that is differ from analogous calculations for large
values of tanβ, where dominated bbh processes, pre-
sented in Fig.7.
The kinematics of the process pp → H → hh →
bbττ is presented by calculations of differential cross
sections with respect to the Higgs transverse momen-
tum pt and pseudorapidity η at 14 TeV, Fig.14
Fig.14. Differential cross sections for Higgs boson,
H with respect to the transverse momentum pt (up)
and pseudorapidity η (down) at a center-of-mass
energy of 14 TeV
The character of the differential cross section does not
differ from the previous cases. This fact underscores
the dependence of this characteristic from many oth-
ers factors beyond the parameter space data. Blurred
peak also indicates the large range of emission angles
of the decay products of the Higgs boson with respect
to the axis of the proton-proton collisions.
4. CONCLUSIONS
We have calculated the production of cross sec-
tion on branching fraction, σ × Br for two mecha-
nisms of production and three decay mechanisms of
Higgs bosons within 2HDM model: 1)pp → H → ττ ,
2)pp → A → Zh → llbb, 3) pp → H → hh → bbττ .
With the help of a computer program SusHi were
carried out calculations for 8 TeV, as well as for
the projected at the LHC energies of 14 TeV in the
center-of-mass energy. The obtained calculations
present an increase in the value of σ × Br for three
considered decay processes of the Higgs boson, but
in the third case this increase is insignificant. In
all three cases, were compared cross sections of the
Higgs boson production via gluon-gluon fusion and
b-associated production process and found the pre-
dominance of the (bbϕ) process only for fermionic
decay channel of the Higgs boson, H → ττ , when the
value of tanβ was significant one. In the other two
bozonic decay channels there was a significant excess
of the cross-section of the Higgs boson production
via gluon-gluon fusion for small values of tanβ. For
three considered cases are calculated the differential
cross sections for Higgs boson with respect to the
transverse momentum pt and pseudorapidity η at a
center-of-mass energy of 14 TeV. The distribution of
the differential cross section with respect to pseudo-
rapidity does not detect certain direction of decay
products to the axis of the proton-proton collisions.
References
1. S. Chatrchyan et al. CMS Collaboration. Obser-
vation of a new boson at a mass of 125 GeV with
the CMS experiment at the LHC // Phys. Lett.
2012, v.B716, p.30-61.
2. B. Schrempp, M. Wimmer. Top Quark and
Higgs Boson Masses: Interplay between Infrared
and Ultraviolet Physics // Prog.Part.Nucl.Phys.
1996, v.37, p.1-90, arXiv:hep-ph/9606386.
3. ATLAS, CMS Collaborations. Measurements of
the Higgs boson production and decay rates and
constraints on its couplings from a combined AT-
LAS and CMS analysis of the LHC pp collision
data at s=7 and 8 TeV // JHEP. 2016, v.08,
p.045.
4. G.C. Branco et al. Theory and phenomenology of
two-Higgs-doublet models // Phys. Rept. 2012,
v.516, p.1-102.
5. CMS Collaboration. Search for a neutral MSSM
Higgs boson decaying into tautau at 13 TeV //
CMS-PAS-HIG-16-006 ;
CMS Collaboration. Summary results of high
mass BSM Higgs searches using CMS run-I data
// CMS-PAS-HIG-16-007 ;
CMS Collaboration. Search for a pseudoscalar
boson decaying into a Z boson and the 125 GeV
Higgs boson in llbb final states // Phys. Lett.
2015, v.B748, p.221-243;
CMS Collaboration. Search for resonant Higgs
boson pair production in the bbττ final state //
CMS-PAS-HIG-16-013.
6. M. Spira, A.Djouadi, D.Graudenz and
P.M. Zerwas. Higgs boson production at
the LHC // Nucl. Phys. 1995, v.B453, p.17-82,
hep-ph/9504378.
9
7. SusHi can be downloaded from: http :
//sushi.hepforge.org/.
8. G. Bozzi, S. Catani, D. de Florian, M. Grazz-
ini. Transverse-momentum resummation and the
spectrum of the Higgs boson at the LHC // Nucl.
Phys. 2006, v.B737, p.73-120, hep-ph/0508068;
H. Mantler and M. Wiesemann. Top- and
bottom-mass effects in hadronic Higgs pro-
duction at small transverse momenta through
LO+NLL // arXiv:1210.8263.
9. S. Heinemeyer, W. Hollik, and G. Weiglein. Feyn-
Higgs: A Program for the calculation of the
masses of the neutral CP even Higgs bosons in the
MSSM // Comput. Phys. Commun. 2000, v.124,
p.76-89, hep-ph/9812320.
10. CMS Collaboration. Summary results of high
mass BSM Higgs searches using CMS run-I data
// CMS-PAS-HIG-16-007.
11. CMS Collaboration. Search for a pseudoscalar
boson decaying into a Z boson and the 125 GeV
Higgs boson in llbb final states // Phys. Lett.
2015, v.B748, p.221-243.
12. CMS Collaboration. Search for resonant Higgs
boson pair production in the bbττ final state //
CMS-PAS-HIG-16-013.
ÈÇÓ×ÅÍÈÅ ÑÂÎÉÑÒ ÐÀÑØÈÐÅÍÍÎÃÎ ÑÅÊÒÎÐÀ ÁÎÇÎÍΠÕÈÃÃÑÀ Â
ÐÀÌÊÀÕ 2HDM-ÌÎÄÅËÈ
Ò.Â.Îáèõîä, Å.À.Ïåòðåíêî
Ó÷åò ïîñëåäíèõ ýêñïåðèìåíòàëüíûõ äàííûõ ïî ïîèñêó ðàñøèðåííîãî ñåêòîðà áîçîíîâ Õèããñà, ïî- ëó-
÷åííûõ íà ÁÀÊ ïðè ýíåðãèè ïðîòîí-ïðîòîííîãî âçàèìîäåéñòâèÿ 13 ÒýÂ, ïîçâîëÿåò ïðîâåñòè êîì-
ïüþòåðíîå ìîäåëèðîâàíèå ñâîéñòâ ñóïåðñèììåòðè÷íûõ ÷àñòèö â ðàìêàõ 2HDM-ìîäåëè. Ýêñïåðèìåí-
òàëüíî ïîëó÷åííûå îãðàíè÷åíèÿ íà ïàðàìåòðû ìîäåëè, ó÷òåííûå â èìïëåìåíòèðîâàííîì â SusHi êîäå
FeynHiggs, äàëè íàì âîçìîæíîñòü ïîñ÷èòàòü âåëè÷èíû ñå÷åíèé, øèðèíû ðàñïàäîâ äëÿ òðåõ ìåõàíèçìîâ
ðîæäåíèÿ è ðàñïàäà áîçîíîâ Õèããñà: 1) pp → H → ττ , 2) pp → A → Zh → llbb, 3) pp → H → hh → bbττ
ïðè ýíåðãèè â ñèñòåìå öåíòðà ìàññ 14 ÒýÂ. Ðàññìîòðåííûå ðàñ÷åòû äàþò âîçìîæíîñòü ñäåëàòü âûâîäû
î íåîáõîäèìîñòè ó÷åòà b-àññîöèèðîâàííîãî ïðîöåññà ðîæäåíèÿ áîçîíîâ Õèããñà äëÿ ôåðìèîííîãî êà-
íàëà ðàñïàäà ïðè áîëüøèõ çíà÷åíèÿõ ïàðàìåòðà tanβ. Ïîëó÷åíû ðàñïðåäåëåíèÿ äèôôåðåíöèàëüíûõ
ñå÷åíèé ïî ïîïåðå÷íîìó èìïóëüñó pt è ïî ïñåâäîáûñòðîòå η, è âûÿâëåíû îñîáåííîñòè êèíåìàòèêè ïðî-
äóêòîâ ðàñïàäà áîçîíîâ Õèããñà.
ÂÈÂ×ÅÍÍß ÂËÀÑÒÈÂÎÑÒÅÉ ÐÎÇØÈÐÅÍÎÃÎ ÑÅÊÒÎÐÀ ÁÎÇÎÍI ÕIÃÃÑÀ Â
ÐÀÌÊÀÕ 2HDM-ÌÎÄÅËI
Ò.Â.Îáiõîä, Å.Î.Ïåòðåíêî
Îáëiê îñòàííiõ åêñïåðèìåíòàëüíèõ äàíèõ ç ïîøóêó ðîçøèðåíîãî ñåêòîðà áîçîíiâ Õiããñà, îòðèìàíèõ
íà ÁÀÊ ïðè åíåðãi¨ ïðîòîí-ïðîòîííîãî çiòêíåííÿ 13 ÒåÂ, äîçâîëÿ¹ ïðîâåñòè êîìï'þòåðíå ìîäåëþ-
âàííÿ âëàñòèâîñòåé ñóïåðñèìåòðè÷íèõ ÷àñòèíîê ó ðàìêàõ 2HDM-ìîäåëi. Åêñïåðèìåíòàëüíî îòðèìàíi
îáìåæåííÿ íà ïàðàìåòðè ìîäåëi, ÿêi âðàõîâàíi â iìïëåìåíòîâàíîìó â SusHi êîäi FeynHiggs, äàëè íàì
ìîæëèâiñòü ïîðàõóâàòè ïåðåðiçè, øèðèíè ðîçïàäiâ äëÿ òðüîõ ìåõàíiçìiâ íàðîäæåííÿ i ðîçïàäó áîçîíiâ
Õiããñà: 1) pp → H → ττ , 2) pp → A → Zh → llbb, 3) pp → H → hh → bbττ ïðè åíåðãi¨ â ñèñòåìi öåíòðà
ìàñ 14 ÒåÂ. Ðîçãëÿíóòi ðîçðàõóíêè äàþòü ìîæëèâiñòü çðîáèòè âèñíîâêè ïðî íåîáõiäíiñòü âðàõóâàí-
íÿ b-àñîöiéîâàíîãî ïðîöåñó íàðîäæåííÿ áîçîíiâ Õiããñà äëÿ ôåðìiîííîãî êàíàëó ðîçïàäó ïðè âåëèêèõ
çíà÷åííÿõ ïàðàìåòðà tanβ. Îòðèìàíî ðîçïîäiëè äèôåðåíöiàëüíèõ ïåðåðiçiâ ïî ïîïåðå÷íîìó iìïóëüñó
pt i ïî ïñåâäîøâèäêîñòi η, i âèÿâëåíî îñîáëèâîñòi êiíåìàòèêè ïðîäóêòiâ ðîçïàäó áîçîíiâ Õiããñà.
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