低温下模量驱动的重子对称与暗物质共生成机制

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本文主要探讨了模量在宇宙早期的物理过程中如何引发重子不对称性和暗物质的共同生成，这个过程被称为"模态诱导的联合生成"。研究基于IIB型大体积弦理论框架，这是弦理论中的一种复杂且精细的模型，用于描述宇宙的微观结构。在这个模型中，除了标准模型的最小超对称标准模型(MSSM)超场外，额外引入了三对色彩三重态和单重态超场。关键假设是，单重态费米子质量约为几百GeV，而色彩三重态费米子的质量则在TeV级别。这些新的超场在理论中扮演着重要角色。模态衰变是驱动这一过程的关键环节。当模态主要衰变为额外的三重态超场时，它为后续的物理过程提供了能量和可能性。在软超对称(SUSY)破缺之后，色彩三重态超场的标量部分的最轻本征态进一步衰变为单重态超场和普通夸克的费米子成分。值得注意的是，这个过程保持了重子数守恒，避免了在基本相互作用中违反重子数守恒定律。通过引入一个离散的Z2对称性，确保了单重态费米子不会进一步衰变成标准模型粒子，这使得它们成为稳定的不对称暗物质(ADM)成分。这种稳定性是解释暗物质作为宇宙主要组成成分之一的重要特性。文章指出，这种机制能够在低 reheating 温度下同时产生观察到的宇宙重子不对称性和暗物质密度，从而解决了宇宙学中的一大谜团——为什么这两个重要的物理参数会如此巧合地与观测相符。这项工作提供了一个新颖的途径，将重子不对称性和暗物质的起源与高能物理中的弦理论和超对称理论相结合，为我们理解宇宙早期的演化提供了重要见解。

Physics Letters B 756 (2016) 376–383

Contents lists available at ScienceDirect

Physics Letters B

www.elsevier.com/locate/physletb

Moduli induced cogenesis of baryon asymmetry and dark matter

Mansi Dhuria

a,∗

, Chandan Hati

a,b

, Utpal Sarkar

Physical Research Laboratory, Navrangpura, Ahmedabad 380 009, India

Indian Institute of Technology Gandhinagar, Chandkheda, Ahmedabad 382 424, India

a r t i c l e i n f o a b s t r a c t

Article history:

Received

1 September 2015

Received

in revised form 2 January 2016

Accepted

6 March 2016

Available

online 9 March 2016

Editor:

M. Trodden

Keywords:

Moduli

decay

Baryogenesis

Dark

matter

LVS

We study a cogenesis mechanism in which the observed baryon asymmetry of the universe and the

dark matter abundance can be produced simultaneously at low reheating temperature without violating

baryon number in the fundamental interactions. In particular, we consider a model which can be realized

in the context of type IIB large volume string compactiﬁcations. The matter superﬁelds in this model

include additional pairs of color triplet and singlet superﬁelds in addition to the Minimal Supersymmetric

Standard Model (MSSM) superﬁelds. Assuming that the mass of the additional singlet fermions is O(GeV)

and of the color triplet fermions is O(TeV), we show that the modulus dominantly decays into the

additional color triplet superﬁelds. After soft supersymmetry (SUSY) breaking, the lightest eigenstate of

scalar component of color triplet superﬁeld further decays into fermionic component of singlet superﬁeld

and quarks without violating baryon number. Imposing discrete Z

symmetry, it follows that the singlet

fermion will not further decay into the SM particles and therefore it can be considered as a stable

asymmetric dark matter (ADM) component. We ﬁnd that the decay of the lightest eigenstate of scalar

component of color triplet superﬁeld gives the observed baryon asymmetry in the visible sector, an

asymmetric dark matter component with the right abundance and naturally explains cosmic coincidence.

(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP

1. Introduction

In cosmology some of the important puzzles are related to the

origin of baryon asymmetry of the universe and the nature of dark

matter. The comparable values of dark matter density and baryon

density [1] 

∼ 5 

points to the possibility that they

might have a common origin. However, the standard paradigm

adopts completely different mechanisms to explain observable

baryon asymmetry of the universe and dark matter abundance.

The baryon asymmetry is generated from an initially baryon–

antibaryon

symmetric universe by considering baryon number (B),

C and CP violating processes that went out of equilibrium in the

early universe, while the dark matter density is produced by con-

sidering

weakly interacting massive particles (WIMPs) (with mass

around O(100) GeV) with the relic density being determined by

the freeze out condition. The fact that they have a comparable

abundance is often referred to as the “cosmic coincidence” puz-

zle.

Recently, the CDMS Collaboration has reported an excess in the

Corresponding author.

E-mail

addresses: mansi@prl.res.in (M. Dhuria), chandan@prl.res.in (C. Hati),

utpal@prl.res.in (U. Sarkar).

dark matter events [2] which sets an upper limit of O(10

−41

) cm

on the value of spin-independent (SI) dark matter-nucleon cross

section for dark matter mass around 10 GeV at 3.1σ signiﬁcance

level. The excess reported by the CoGeNT Collaboration [3] also

hints at a light dark matter mass, almost in the same region of pa-

rameter

space. The data taken by the XENON100 experiment [4]

also

gives a very stringent constraint on SI dark matter-nucleon

cross section which points towards a dark matter mass around

O(GeV). The light dark matter is often also motivated due to the

possibility of explaining 3.5 KeV X-ray line by radiative decay of

O(GeV) neutral dark matter particle [5]. However, for an O(GeV)

mass the thermal WIMPs give over-abundance of dark matter par-

ticle

for annihilation cross-section less than 10

−26

, and thus

the alternative schemes where an O(GeV) mass dark matter can

be accommodated have gained signiﬁcant attention. To this end,

the cogenesis scenarios are particularly interesting because they

have an attractive feature of explaining the observed baryon asym-

metry

of the universe together with an asymmetric dark matter

component which can naturally satisfy the criterion for O(GeV)

mass dark matter. Furthermore, the apparent coincidence of the

baryon and dark matter densities can also be addressed in such

a framework using the underlying connection between the baryo-

genesis

scenarios and dark matter production. There exist several

http://dx.doi.org/10.1016/j.physletb.2016.03.018

0370-2693/

SCOAP

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