  Diversity, Equity, Inclusion, and Accessibility (DEIA) are not only called
for to ensure morality and justice in our society, they also support ongoing
and future excellence in particle physics. Over the past decade, the particle
physics community has devised programs to support DEIA along multiple axes, and
the way we think about measuring and implementing these initiatives has
evolved. DEIA in physics is a broad topic, so in this paper we focus on the
experiences of marginalized communities and outline ways different stakeholders
can build a culture of equitable access for the success of marginalized
individuals. Specifically, we identify urgent needs in the following areas: (1)
We need to acquire a better understanding of the status quo, both
quantitatively and qualitatively, to assess the effectiveness of existing
programs and to develop best practices; (2) we need to develop effective and
inclusive ways to engage marginalized communities; (3) we need to create
infrastructure to better support members of marginalized communities, on an
academic, financial and personal level; (4) we need to create an environment
conducive to equitable access and success by establishing community
expectations, fostering inclusion in social interactions, and holding
individuals and institutions accountable; and (5) we need to establish a
mechanism to monitor progress in the area of DEIA, including the implementation
of the recommendations enumerated in this paper and others during the Snowmass
2021 process.
