A light pseudoscalar of 2HDM confronted with muon g-2 and experimental constraints
Received: February
A light pseudoscalar of 2HDM confronted with muon g-2 and experimental constraints
Lei Wang 0 1
Xiao-Fang Han 0 1
Open Access 0 1
c The Authors. 0 1
0 Department of Physics, Yantai University
1 [32] A. Broggio, E.J. Chun, M. Passera, K.M. Patel and S.K. Vempati , Limiting
A light pseudoscalar of the lepton-specific 2HDM can enhance the muon g-2, but suffer from various constraints easily, such as the 125.5 GeV Higgs signals, nonobservation of additional Higgs at the collider and even Bs +. In this paper, we take the light CP-even Higgs as the 125.5 GeV Higgs, and examine the implications of those observables on a pseudoscalar with the mass below the half of 125.5 GeV. Also the other relevant theoretical and experimental constraints are considered. We find that the pseudoscalar can be allowed to be as low as 10 GeV, but the corresponding tan , sin( ) and the mass of charged Higgs are strongly constrained. In addition, the surviving samples favor the wrong-sign Yukawa coupling region, namely that the 125.5 GeV Higgs couplings to leptons have opposite sign to the couplings to gauge bosons and quarks.
confronted; with; muon; Higgs Physics; Beyond Standard Model
1 Introduction L2HDM 2 3
Numerical calculations
Results and discussions
The ATLAS and CMS Collaborations found a 125.5 GeV Higgs boson at the LHC [1,
2]. The latest experimental data show that the properties of this particle agree with the
Standard Model (SM) predictions. Especially the diphoton signal strength is changed from
signal data can give the strong constraints on the effects of new physics.
The two-Higgs-doublet model (2HDM) has very rich Higgs phenomenology, including
two neutral CP-even Higgs bosons h and H, one neutral pseudoscalar A, and two charged
Higgs H. The recent Higgs data have been used to constrain the 2HDM, see some recent
magnetic moment [2832]. Due to the experimental constraints, the type-II 2HDM [33, 34]
is very difficult to explain the muon g-2 anomaly [30, 32], but the lepton-specific 2HDM
(L2HDM) [3540] can still give a valid explanation [31, 32]. Compared to the recent
to account for the muon g-2 anomaly. For a light pseudoscalar, the 125.5 GeV Higgs
additional important contributions from the very light pseudoscalar exchange diagrams.
constraints on the very light pseudoscalar. Also we consider the theoretical constraints,
electroweak precision data, the non-observation of additional Higgs at collider, and the
Our work is organized as follows. In section 2 we recapitulate the L2HDM. In section 3
we introduce the numerical calculations. In section 4, we show the implications of muon
g-2 and experimental data on the L2HDM. Finally, we give our conclusion in section 5.
The general Higgs potential is written as [41]
V = m121(11) + m222(22) hm122(12 + h.c.)i
two neutral CP-even h and H, one neutral pseudoscalar A, and two charged scalar H.
is zero. In the Higgs basis, the mass eigenstates are obtained from
A = a2,
yVA = 0,
The right fields of the equations denote the interaction eigenstates in the Higgs basis. The
corresponding masses and couplings of eq. (2.1) are changed in the Higgs basis [42]. For
In the Higgs basis, the general Yukawa interactions with no tree-level FCNC are
LY = v
The couplings of neutral Higgs bosons with respect to the SM Higgs boson are give by
Where V denotes Z and W , and f denotes u, d and `. The charged Higgs couplings are
LY = v
u [d VCKMMdPR u MuVCKMPL] d + ` M`PR` + h.c.,
where Mf are the diagonal fermion mass matrices.
Numerical calculations
constraints from the vacuum stability, unitarity and coupling-constant perturbativity, and
exclusion constraints from the neutral and charged Higgses searches at the LEP, Tevatron
and LHC at 95% confidence level. Now we introduce the calculations of some constraints,
which are the main motivations of this paper:
duced by the Higgs bosons and also from the two-loop Barr-Zee diagrams mediated by A,
h and H. For the one-loop contributions [5254],
where j = h, H, A, H, rj = m2/Mj2. For rj
fh,H (r) ' ln r 7/6, fA(r) ' ln r + 11/6, fH (r) ' 1/6.
For two-loop contributions,
X Nfc Qf2 yi yfi rfi gi(rfi ),
degrees of freedom of the fermion f in the loop. The functions gi(r) are [2830]
gh,H (r) =
2x(1 x) 1
x(1 x) r
x(1 x)
gA(r) =
x(1 x) r
x(1 x)
ones. In the L2HDM, since the CP-odd Higgs coupling to the tau lepton is proportional
Global fit to the 125.5 GeV Higgs signal data:
we take the light CP-even Higgs as
the 125.5 GeV Higgs. Using the method taken in [5560], we perform a global fit to the
125.5 GeV Higgs data of 29 channels after ICHEP 2014, which are summarized in the tables
I-V of [61]. A number of new measurements or updates of existing ones were presented
by ATLAS and CMS Collaborations [3, 4, 6272]. The signal strength for the i channel is
i = igghRggH + iVBFRVBF + iV H RV H + ittH RttH .
ij denotes the assumed signal composition of the partonic process j, which are given in
tables I-V of [61]. For an un (...truncated)