content_image/343370.jpg content_image/343367.jpg content_image/343368.jpg
models in connection to the type II seesaw mechanism for neutrino masses (see, e.g. Ref. [13]). 

This paper is organized as follows: in Sec. II, we discuss the main features of the model and focus on the decay of DM particle induced by the soft C -breaking terms. In Sec. III, we calculate the DM decay signals which includes the positron fraction, total flux of electron and positron, neutrino-induced muon flux and high energy gamma-ray flux. The results are summarized in Sec. IV. 

## II. DECAYING DARK MATTER IN A LR SYMMETRIC MODEL 

We begin with a brief review of the LR model with two Higgs bidoublets described in Ref. [15, 16]. The model is a simple extension to the minimal LR model [17], which is based on the gauge group SU (2)$_{L}$ ⊗ SU (2)$_{R}$ ⊗ U (1)$_{B}$$_{−}$$_{L}$. The left- and right-handed fermions belong to the SU (2)$_{L}$ and SU (2)$_{R}$ doublets respectively. The Higgs sector contains two Higgs bidoublets φ (2,2 $^{∗}$,0), χ (2,2 $^{∗}$,0), a left(right)-handed Higgs triplet Δ$_{L}$$_{(}$$_{R}$$_{)}$ (3(1),1(3),2), and a gauge singlet S (0,0,0) with the following flavor contents 

<img src='content_image/343370.jpg'>

The two triplets Δ$_{L,R}$ are responsible for breaking the left-right symmetry at high energy scale and generating small neutrino masses through the seesaw mechanism. The introduction of Higgs bidoublets φ and χ accounts for the electroweak symmetry breaking and overcome the fine-tuning problem in generating the spontaneous CP violation in the minimal LR model. Meanwhile it also relaxes the severe low energy phenomenological constraints. The gauge singlet S is relevant to the DM candidate. 

The kinematic terms for the scalar fields are given by 

<img src='content_image/343367.jpg'>

where 

<img src='content_image/343368.jpg'>

