153 research outputs found
High Energy pp Elastic Scattering in Condensate Enclosed Chiral Bag Model and TOTEM Elastic Measurements at LHC at 7 TeV
We study high energy and elastic
scattering in the TeV region based on an effective field theory model of the
proton. We phenomenologically investigate the main processes underlying elastic
scattering and quantitatively describe the measured elastic
d/dt at energies 7.0 TeV (LHC ), 1.96 TeV
(Tevatron ), and 0.630 TeV (SPS ). Finally, we give our prediction for elastic
d/dt at 14 TeV that will be measured by the TOTEM
Collaboration.Comment: Presented at EDS Blois 2013 (arXiv:1309.5705
pp Elastic Scattering at LHC in a Nucleon-Structure Model
We predict pp elastic differential cross sections at LHC at c.m. energy 14
TeV and momentum transfer range |t| = 0 - 10 GeV*2 in a nucleon-structure
model. In this model, the nucleon has an outer cloud of quark-antiquark
condensed ground state, an inner shell of topological baryonic charge (r ~
0.44F) probed by the vector meson omega, and a central quark-bag (r ~ 0.2F)
containing valence quarks. We also predict elastic differential cross section
in the Coulomb-hadronic interference region. Large |t| elastic scattering in
this model arises from valence quark-quark scattering, which is taken to be due
to the hard-pomeron (BFKL pomeron with next to leading order corrections). We
present results of taking into account multiple hard-pomeron exchanges, i.e.
unitarity corrections. Finally, we compare our prediction of pp elastic
differential cross section at LHC with the predictions of various other models.
Precise measurement of pp elastic differential cross section at LHC by the
TOTEM group in the |t| region 0 - 5 GeV*2 will be able to distinguish between
these models.Comment: To be published in the Proceedings of the 12th International
Conference on Elastic and Diffractive Scattering, DESY, Hamburg. Presented by
M. M. Islam, May 200
Deep-Elastic pp Scattering at LHC from Low-x Gluons
Deep-elastic pp scattering at c.m. energy 14 TeV at LHC in the momentum
transfer range 4 GeV*2 < |t| < 10 GeV*2 is planned to be measured by the TOTEM
group. We study this process in a model where the deep-elastic scattering is
due to a single hard collision of a valence quark from one proton with a
valence quark from the other proton. The hard collision originates from the
low-x gluon cloud around one valence quark interacting with that of the other.
The low-x gluon cloud can be identified as color glass condensate and has size
~0.3 F. Our prediction is that pp differential cross section in the large |t|
region decreases smoothly as momentum transfer increases. This is in contrast
to the prediction of pp differential cross section with visible oscillations
and smaller cross sections by a large number of other models.Comment: 10 pages, including 4 figure
p p Elastic Scattering at LHC and Nucleon Structure
High energy elastic scattering at the Large Hadron Collider (LHC) at
c.m. energy 14 TeV is predicted using the asymptotic behavior of
and known from dispersion relation calculations and
the measured elastic differential cross section at . The effective field theory model underlying the phenomenological
analysis describes the nucleon as having an outer cloud of quark-antiquark
condensed ground state, an inner core of topological baryonic charge of radius
and a still smaller valence quark-bag of radius . The LHC experiment TOTEM (Total and Elastic Measurement), if carried
out with sufficient precision from to , will be
able to test this structure of the nucleon.Comment: 13 pages, 6 figures, to be published in the Modern Physics Letters
Near Forward pp Elastic Scattering at LHC and Nucleon Structure
High energy proton-proton and antiproton-proton elastic scattering are
studied first in a model where the nucleon has an outer cloud and an inner
core. Elastic scattering is viewed as due to two processes: a) diffraction
scattering originating from cloud-cloud interaction; b) a hard or large |t|
scattering originating from one nucleon core scattering off the other via
vector meson omega exchange, while their outer clouds interact independently.
The omega-exchange amplitude shows that omega behaves like an elementary vector
meson at high energy, contrary to a regge pole behavior. This behavior,
however, can be understood in the nonlinear sigma-model where omega couples to
a topological baryonic current like a gauge boson, and the nucleon is described
as a topological soliton. Further investigation shows that the underlying
effective field theory model is a gauged linear sigma-model that has not only
the pion sector and the Wess-Zumino-Witten action of the nonlinear sigma-model,
but also a quark-scalar sector. The nucleon structure that emerges is that the
nucleon has an outer cloud of quark-antiquark condensed ground state, an inner
core of topological baryonic charge probed by omega, and a still smaller
quark-bag containing massless valence quarks. Large |t| pp elastic scattering
is attributed to valence quark-quark elastic scattering, which is taken to be
due to the hard pomeron. The model is applied to predict pp elastic
differential cross section at LHC at c.m. energy 14 TeV and |t| = 0 - 10 GeV*2.
If our predicted differential cross section is quantitatively confirmed by
precise measurement at LHC by the TOTEM group, then it will indicate that
various novel ideas developed over the last four decades to describe the
nucleon combine and lead to a unique physical description of its structure.Comment: 49 pages including 17 figures. Submitted to Int. J. Mod. Phys.
Tumor-immune metaphenotypes orchestrate an evolutionary bottleneck that promotes metabolic transformation
Introduction: Metabolism plays a complex role in the evolution of cancerous tumors, including inducing a multifaceted effect on the immune system to aid immune escape. Immune escape is, by definition, a collective phenomenon by requiring the presence of two cell types interacting in close proximity: tumor and immune. The microenvironmental context of these interactions is influenced by the dynamic process of blood vessel growth and remodelling, creating heterogeneous patches of well-vascularized tumor or acidic niches. Methods: Here, we present a multiscale mathematical model that captures the phenotypic, vascular, microenvironmental, and spatial heterogeneity which shapes acid-mediated invasion and immune escape over a biologically-realistic time scale. The model explores several immune escape mechanisms such as i) acid inactivation of immune cells, ii) competition for glucose, and iii) inhibitory immune checkpoint receptor expression (PD-L1). We also explore the efficacy of anti-PD-L1 and sodium bicarbonate buffer agents for treatment. To aid in understanding immune escape as a collective cellular phenomenon, we define immune escape in the context of six collective phenotypes (termed “meta-phenotypes”): Self-Acidify, Mooch Acid, PD-L1 Attack, Mooch PD-L1, Proliferate Fast, and Starve Glucose. Results: Fomenting a stronger immune response leads to initial benefits (additional cytotoxicity), but this advantage is offset by increased cell turnover that leads to accelerated evolution and the emergence of aggressive phenotypes. This creates a bimodal therapy landscape: either the immune system should be maximized for complete cure, or kept in check to avoid rapid evolution of invasive cells. These constraints are dependent on heterogeneity in vascular context, microenvironmental acidification, and the strength of immune response. Discussion: This model helps to untangle the key constraints on evolutionary costs and benefits of three key phenotypic axes on tumor invasion and treatment: acid-resistance, glycolysis, and PD-L1 expression. The benefits of concomitant anti-PD-L1 and buffer treatments is a promising treatment strategy to limit the adverse effects of immune escape
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