26,057 research outputs found
Producing baryons from neutralinos in small H2 clumps over cosmological ages
Extreme scattering events in quasars suggest the existence of dark
clumps of mass and size . Such
clumps are extremely dense compared to WIMPs clumps of the same mass obtained
by N-body simulations. A WIMP clump gravitationally attracted by a central clump would experience a first infall during which its density increases
by in . In this poster I begin to explore the
phenomenology of mixed clumps made with and WIMPs. Molecular clouds
built with clumps are efficient machines to transform smooth distributions of
WIMPs into concentrated networks. If WIMPs are neutralinos gravitationally
attracted in clumps of such molecular clouds, they may either enrich the baryon
sector over cosmological ages, or remain mixed with cold clouds
until the clumps evaporate either by collision or by stellar UV heating. A
phenomenological model based on an hypothetic dark baryonic component (DBC)
that was invoked in the past to explain one of the main drawbacks of CDM
profiles, their overly dense cores, is briefly revisited in this context. The
DBC is replaced by a mix of and WIMPs, with a small fraction of HI
produced by internal collisions, in slightly dispersive clumpy
clouds that may migrate from the halo towards inner parts of a galaxy and disk.Comment: 6 pages, 1 figure, submitted to Conference: XII International
Symposium on Nuclei in the Cosmos August 5-12, 2012 Cairns, Australi
Chinese Religious Syncretism in Macau
In this paper I address the phenomenon of syncretism with respect to Chinese
religions. An analysis of the syncretism that takes place between the three major
Chinese religious traditions is first done in its personal and social dimensions. The
social structure of Chinese religion is then used as a framework to understand how
Buddhism and Daoism were made compatible with Confucianism. All this will serve
as a background for the case study of Macau, where Chinese religious syncretism
is very much alive. Three popular religious festivals are celebrated annually and simultaneously on the eighth day of the fourth lunar month, namely, zuilongjie (醉龍節) Feast of the Drunken Dragon, tangongdan (譚公誕) Tam Kung Festival and fodanjie
(佛誕節) Feast of the Buddha
Cronin effect and high-p_T suppression from the Color Glass Condensate
I give a pedagogical survey of the nuclear collective effects associated with
gluon saturation and their impact on particle production in high-energy proton
(or deuteron)-nucleus collisions at RHIC. At central rapidity, the theory
predicts a Cronin peak due to independent multiple scattering off the valence
quarks in the nucleus. At forward rapidities, the peak flattens out and
disappears very fast, because of the correlations induced through quantum
evolution in the nuclear gluon distribution at small x. Also, the ratio R_{pA}
between the particle yield in proton-nucleus and proton-proton collisions is
rapidly suppressed when increasing the rapidity, because of saturation effects
which slow down the evolution of the nucleus compared to that of the proton.
This behaviour could be responsible for a similar trend observed in the
deuteron-nucleus collisions at RHIC.Comment: 22 pages, 10 eps figures, Invited talk at the International Workshop
IX Hadron Physics and VII Relativistic Aspects of Nuclear Physics
(HADRON-RANP 2004), Angra dos Reis, Brasil, March 28--April 03, 200
Gluon Saturation at small x
At very high energies, the relevant component of the hadron wavefunction can
be described as a Color Glass Condensate, i.e., a state of high density gluonic
matter whose distribution is random, but frozen over the relevant time scales.
The weight function for this distribution obeys a renormalization group
equation in the form of a functional Fokker-Planck equation. Its solution leads
to an effective theory which predicts gluon saturation at sufficiently high
energy, or small Bjorken's .Comment: 8 pages, talk given at XXXI International Symposium on Multiparticle
Dynamics, Sept 1-7, 2001, Datong China. URL http://ismd31.ccnu.edu.cn
Wisdom in Aristotle and Aquinas: From Metaphysics to Mysticism
This essay contains an attempt to trace the evolution of the concept of wisdom as found in the thought of Aristotle and Aquinas in terms of how the philosophical concept of wisdom as an intellectual virtue is understood and used to express the theological concept of wisdom as a gift of the Holy Spirit. The main aim is to understand how Aquinas derived the concept of wisdom from Aristotle's metaphysics and developed it in his mysticism. This research is based on a close study of Book Six of Aristotle's Nichomachean Ethics, the corresponding sections of Aquinas' Sententia
libri Ethicorum and question forty-five of the second part of the second part of Aquinas' Summa Theologiae. The insights gained from the study are then used to decipher the theoretical meaning of Augustine's famous saying: "love and do
what thou wilt" and to expound on the practical value of wisdom for religious leaders
The non-linear evolution of jet quenching
We construct a generalization of the JIMWLK Hamiltonian, going beyond the
eikonal approximation, which governs the high-energy evolution of the
scattering between a dilute projectile and a dense target with an arbitrary
longitudinal extent (a nucleus, or a slice of quark-gluon plasma). Different
physical regimes refer to the ratio between the longitudinal size
of the target and the lifetime of the gluon fluctuations. When , meaning that the target can be effectively treated as a shockwave, we
recover the JIMWLK Hamiltonian, as expected. When , meaning that
the fluctuations live inside the target, the new Hamiltonian governs phenomena
like the transverse momentum broadening and the radiative energy loss, which
accompany the propagation of an energetic parton through a dense QCD medium.
Using this Hamiltonian, we derive a non-linear equation for the dipole
amplitude (a generalization of the BK equation), which describes the
high-energy evolution of jet quenching. As compared to the original BK-JIMWLK
evolution, the new evolution is remarkably different: the plasma saturation
momentum evolves much faster with increasing energy (or decreasing Bjorken's
) than the corresponding scale for a shockwave (nucleus). This widely opens
the transverse phase-space for the evolution and implies the existence of large
radiative corrections, enhanced by the double logarithm , with
the temperature of the medium. This confirms and explains from a physical
perspective a recent result by Liou, Mueller, and Wu (arXiv:1304.7677). The
dominant corrections are smooth enough to be absorbed into a renormalization of
the jet quenching parameter . This renormalization is controlled by a
linear equation supplemented with a saturation boundary, which emerges via
controlled approximations from the generalized BK equation alluded to above.Comment: 54 pages plus 4 appendices, 6 figure
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