1,120 research outputs found
FASER: ForwArd Search ExpeRiment at the LHC
New physics has traditionally been expected in the high- region at
high-energy collider experiments. If new particles are light and
weakly-coupled, however, this focus may be completely misguided: light
particles are typically highly concentrated within a few mrad of the beam line,
allowing sensitive searches with small detectors, and even extremely
weakly-coupled particles may be produced in large numbers there. We propose a
new experiment, ForwArd Search ExpeRiment, or FASER, which would be placed
downstream of the ATLAS or CMS interaction point (IP) in the very forward
region and operated concurrently there. Two representative on-axis locations
are studied: a far location, from the IP and just off the beam
tunnel, and a near location, just from the IP and right behind
the TAN neutral particle absorber. For each location, we examine leading
neutrino- and beam-induced backgrounds. As a concrete example of light,
weakly-coupled particles, we consider dark photons produced through light meson
decay and proton bremsstrahlung. We find that even a relatively small and
inexpensive cylindrical detector, with a radius of and
length of , depending on the location, can discover dark photons
in a large and unprobed region of parameter space with dark photon mass and kinetic mixing parameter . FASER will clearly also be sensitive to many other forms of
new physics. We conclude with a discussion of topics for further study that
will be essential for understanding FASER's feasibility, optimizing its design,
and realizing its discovery potential.Comment: 35 Pages, 12 figures. Version 2, references added, minor change
Three-Body Decays of Sleptons with General Flavor Violation and Left-Right Mixing
We determine the widths of three-body decays of sleptons, ,
in the presence of arbitrary slepton flavor violation and left-right mixing.
These decays are important in scenarios in which the lightest supersymmetric
particle is the gravitino, a generic possibility in models with gauge- and
gravity-mediated supersymmetry breaking. Three-body decays have been discussed
previously assuming flavor conservation and left-right mixing in only the stau
sector. Flavor violation and general left-right mixing open up many new decay
channels, which provide new avenues for precision mass measurements and may
play an essential role in solving the standard model flavor problem. We present
results for toy models with two-generation mixing, and discuss the
implementation of these results in SPICE, a program that simplifies collider
event simulations of flavor-violating supersymmetric models.Comment: 25 pages, 5 figures; v2: published versio
Script para análises de experimentos de competição pelo método substitutivo no "R".
Utilidade do Script; Antes de Iniciar; Executando o Script; Solução de Problemas.bitstream/item/114713/1/DOC2014124-com-Anexos.pd
From mice to humans: Developments in cancer immunoediting
Cancer immunoediting explains the dual role by which the immune system can both suppress and/or promote tumor growth. Although cancer immunoediting was first demonstrated using mouse models of cancer, strong evidence that it occurs in human cancers is now accumulating. In particular, the importance of CD8+ T cells in cancer immunoediting has been shown, and more broadly in those tumors with an adaptive immune resistance phenotype. This Review describes the characteristics of the adaptive immune resistance tumor microenvironment and discusses data obtained in mouse and human settings. The role of other immune cells and factors influencing the effector function of tumor-specific CD8+ T cells is covered. We also discuss the temporal occurrence of cancer immunoediting in metastases and whether it differs from immunoediting in the primary tumor of origin
Glyphosate translocation in herbicide tolerant plants
The objective of this study was to evaluate glyphosate translocation in glyphosate-tolerant weed species (I. nil, T. procumbens and S. latifolia) compared to glyphosate-susceptible species (B. pilosa). The evaluations of 14C-glyphosate absorption and translocation were performed at 6, 12, 36 and 72 hours after treatment (HAT) in I. nil and B. pilosa, and only at 72 HAT in the species T. procumbens and S. latifolia. The plants were collected and fractionated into application leaf, other leaves, stems, and roots. In S. latifolia, approximately 88% of the glyphosate remained in the application leaf and a small amount was translocated to roots at 72 HAT. However, 75% of the herbicide applied on T. procumbens remained in the leaf that had received the treatment, with greater glyphosate translocation to the floral bud. It was concluded that the smaller amount of glyphosate observed in S. latifolia and T. procumbens may partly account for their higher tolerance to glyphosate. However, I. nil tolerance to glyphosate may be associated with other factors such as metabolization, root exudation or compartmentalization, because a large amount of the herbicide reached the roots of this species.Objetivou-se neste estudo avaliar a translocação de glyphosate em plantas tolerantes (Ipomoea nil, Tridax procumbens e Spermacoce latifolia) e suscetível (Bidens pilosa) a esse herbicida. As avaliações de absorção e translocação do 14C-glyphosate em I. nil e B. pilosa foram efetuadas às 6, 12, 36 e 72 horas após a aplicação do herbicida (HAT), e em T. procumbens e S. latifolia, às 72 HAT. As plantas foram coletadas e fracionadas em: folha de aplicação, demais folhas, caules e raízes; em T. procumbens e S. latifolia, avaliou-se a presença do produto na inflorescência da planta. Em S. latifolia, aproximadamente 88% do glyphosate permaneceu na folha de aplicação, e pequena quantidade translocou para as raízes. Todavia, em T. procumbens, 75% do herbicida permaneceu na folha que recebeu a aplicação, observando-se maior translocação na inflorescência em relação às raízes. Conclui-se que a menor translocação do glyphosate observada em S. latifolia e T. procumbens pode ser um dos fatores responsáveis pela maior tolerância dessas espécies ao herbicida, ao passo que em I. nil a metabolização, a exsudação radicular ou a compartimentalização podem favorecer a tolerância, já que grande quantidade do produto atingiu as raízes da espécie
Phytosociological surveys: tools for weed science?
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Previous issue date: 2013-11-08201
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