狄拉克中微子与Z4对称性下的暗物质稳定性：一种新型关联

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本文探讨了将暗物质的稳定性与中微子的狄拉克性质相联系的可能性，提出了一种基于Z4离散轻子数对称性的简单理论框架。在这一理论模型中，被称为I型跷跷板机制（Type-I seesaw mechanism）被用来生成微小的狄拉克中微子质量。这种机制暗示了可能存在一种稳定的弱相互作用大质量粒子（Weakly Interacting Massive Particles, WIMPs），即暗物质候选者。 Z4离散对称性在物理学中扮演着关键角色，因为它能够保证中微子的狄拉克率（Dirac mass）保持一致，这是狄拉克中微子理论的一个核心特性，即它们具有双重态，既有左旋也有右旋版本。在标准模型中，中微子被认为是Majorana粒子，即它们自旋和粒子-反粒子是重合的，但若它们是狄拉克粒子，则意味着它们具有独特的物理性质，如具有质量且可以与其他粒子发生干涉效应。通过I型跷跷板机制，一个大的对称性破缺（symmetry breaking）发生在高能量层面上，产生小的中微子质量，同时保持了暗物质候选物的稳定性。这种稳定性源于Z4对称性的残留效应，它确保即使在低能量宇宙中，暗物质粒子仍能保持其质量不变，从而符合暗物质的基本特征——在宇宙的大部分时间里不参与强相互作用，且在宇宙早期即冻结其数量。在本文中，作者Salvador Centelles-Chuliá、Ernest Mab、Rahul Srivastava和José W. F. Valle来自西班牙瓦伦西亚大学和加州大学河滨分校的研究团队，结合了中微子物理学与暗物质理论，提供了一个创新的视角来解释这两个未解谜团之间的潜在联系。他们所提出的理论不仅为解决中微子质量问题提供了新的途径，还为寻找实验验证暗物质候选物的可能性提供了理论支持。研究结果于2017年发表在《物理学快报B》上，可供物理学家们进一步讨论和验证这个引人入胜的假设。

Physics Letters B 767 (2017) 209–213

Contents lists available at ScienceDirect

Physics Letters B

www.elsevier.com/locate/physletb

Dirac neutrinos and dark matter stability from lepton quarticity

Salvador Centelles Chuliá

, Ernest Ma

, Rahul Srivastava

a,c,∗

, José W.F. Valle

AHEP Group, Instituto de Física Corpuscular – C.S.I.C./Universitat de València, Ediﬁcio de Institutos de Paterna, C/Catedratico José Beltrán, 2 E-46980 Paterna

(València) -Spain

Physics Department, University of California, Riverside, CA 92521, USA

Physical Research Laboratory, Navrangpura, Ahmedabad - 380 009, India

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

Article history:

Received

14 November 2016

Received

in revised form 13 January 2017

Accepted

30 January 2017

Available

online 2 February 2017

Editor: A.

Ringwald

We propose to relate dark matter stability to the possible Dirac nature of neutrinos. The idea is illustrated

in a simple scheme where small Dirac neutrino masses arise from a type-I seesaw mechanism as a result

of a Z

discrete lepton number symmetry. The latter implies the existence of a viable WIMP dark matter

candidate, whose stability arises from the same symmetry which ensures the Diracness of neutrinos.

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

Amongst the major shortcomings of the Standard Model are the

neutrino mass and the dark matter problems. Underpinning the

origin of neutrino mass and elucidating the nature of dark mat-

ter

would constitute a gigantic step forward in particle physics.

Here we focus on the possibility that the neutrino mass and dark

matter problems may be closely interconnected [1,2]. Concerning

neutrino mass a major unknown is whether neutrinos are their

own anti-particles, an issue which has remained an open challenge

ever since Ettore Majorana’s pioneer idea on the quantum mechan-

ics

of spin. On the other hand, since many years physicists have

pondered about what is the dark matter made of, and what makes

it stable, a property usually assumed in an ad-hoc fashion.

Indeed,

although the existence of non-baryonic dark matter is well estab-

lished

by using cosmological and astrophysical probes, its nature

has otherwise remained elusive [5].

The

detection of neutrinoless double beta decay would be a

major step in particle physics since, according to the black-box the-

orem [6,7] it

would not only demonstrate that lepton number is

violated in nature, but also imply that neutrinos are of Majorana

type. On the other hand, the fact that the weak interaction is V-A

turns this quest into a major challenge [8,9]. As of now the nature

of neutrinos remains as mysterious as the mechanism responsible

for generating their small masses. Little is known regarding the

nature of its associated messenger particles, the underlying mass

Corresponding author.

E-mail

addresses: salcen@alumni.uv.es (S. Centelles Chuliá), ma@phyun8.ucr.edu

(E. Ma),

rahulsri@iﬁc.uv.es (R. Srivastava), valle@iﬁc.uv.es (J.W.F. Valle).

Attempts at stabilizing dark matter by using the Z

and Z

symmetries have

already been considered in the literature [3,4].

scale or its ﬂavor structure [10], currently probed only in neutrino

oscillation experiments [11]. Here we assume that neutrinos are

Dirac particles. Realizing this possibility requires extra assumptions

beyond the standard SU(3)

⊗SU(2)

⊗U(1)

electroweak gauge

invariance. One approach is to extend the gauge group itself, for

example, by using the SU(3)

⊗SU(3)

⊗U(1)

gauge structure due

to its special features [12]. In this framework it has recently been

shown how to obtain a type-II seesaw mechanism for Dirac neutri-

nos [13,14].

Using unconventional lepton charges for right handed

neutrinos [15] and gauging B − L can also lead to Dirac neutrinos

within the type-I seesaw mechanism [4,16,17]. Alternatively, one

may stick to the SU(3)

⊗ SU(2)

⊗ U(1)

gauge structure but use

extra ﬂavor symmetries implying a conserved lepton number, so as

to obtain Dirac neutrinos, as suggested in [18].

this letter we focus on having neutrinos as Dirac particles as

a result of the cyclic symmetry Z

, which plays the role of a dis-

crete

version of lepton number, we call quarticity.

We show that

a WIMP dark matter candidate can naturally emerge, stabilized by

quarticity, the same symmetry associated to the Diracness of neu-

trinos.

Our

model is based on the discrete symmetry Z

⊗Z

where Z

is the cyclic group of order four and Z

is the cyclic group of or-

der

two. As we show here, Z

symmetry not only forbids Majorana

terms but also forbids couplings of potential dark matter candi-

date

ensuring stability. Thus, the same symmetry which implies

the

Dirac nature of neutrinos also ensures the stability of dark

matter. The Z

symmetry is required here to ensure the seesaw

It is not inconceivable that such symmetry could arise from anomaly-free dis-

crete

gauge symmetries [19].

http://dx.doi.org/10.1016/j.physletb.2017.01.070

0370-2693/

SCOAP

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