3,976 research outputs found
Theory and phenomenology of non-global logarithms
We discuss the theoretical treatment of non-global observables, those
quantities that are sensitive only to radiation in a restricted region of phase
space, and describe how large `non-global' logarithms arise when we veto the
energy flowing into the restricted region. The phenomenological impact of
non-global logarithms is then discussed, drawing on examples from event shapes
in DIS and energy-flow observables in 2-jet systems. We then describe
techniques to reduce the numerical importance of non-global logarithms, looking
at clustering algorithms in energy flow observables and the study of associated
distribution of multiple observables.Comment: Based on talks presented at the XXXVIIIth Rencontres de Moriond 'QCD
and high-energy hadronic interactions', 8 page
Role of the meson in photoproduction off the deuteron
Neutral kaon photoproduction off the nucleon and deuteron has been
reinvestigated by utilizing the new experimental data on both targets. An
isobar model for elementary operator and impulse approximation for the reaction
on the deuteron have been used. The available free parameters in the elementary
model have been extracted from both elementary and deuteron data. In contrast
to the elementary reaction, fitting the deuteron data requires an inclusion of
weighting factor. The result indicates that the angular distribution of the
elementary process does not show backward peaking behavior.Comment: 4 pages, 4 figures, prepared for the Fifth Asia-Pacific Conference on
Few-Body Problems in Physics 2011 (APFB2011), Seoul, Korea, August 22-26,
201
Discovering baryon-number violating neutralino decays at the LHC.
Recently there has been much interest in the use of single-jet mass and jet substructure to identify boosted particles decaying hadronically at the LHC. We develop these ideas to address the challenging case of a neutralino decaying to three quarks in models with baryonic violation of R parity. These decays have previously been found to be swamped by QCD backgrounds. We demonstrate for the first time that such a decay might be observed directly at the LHC with high significance, by exploiting characteristics of the scales at which its composite jet breaks up into subjets
Quark mass hierarchy in 3-3-1 models
We study the mass spectrum of the quark sector in an special type I-like
model with gauge symmetry . By
considering couplings with scalar triplets at large () and small
() scales, we obtain specific zero-texture mass matrices for the
quarks which predict three massless quarks () and three massive quarks
() at the electroweak scale ( GeV). Taking into account mixing
couplings with three heavy quarks at large scales predicted by the model, the
three massless quarks obtain masses at small order that depends on the inverse
of the large scale. Thus, masses of the form
and can be obtained naturally from the gauge structure of
the model
Partisipasi Masyarakat dalam Peningkatan Kualitas Permukiman Dikawasan Pusat Kota Palu
Keberhasilan pembangunan di era reformasi sekarang ini, khususnya dalam Kegiatan peningkatan kualitas permukiman di kawasan pusat kota, sangat dtentukan oleh adanya partisipasi aktif dan masyarakat. Partisipasi masyarakat dalarn kegiatan ini tentunya dipengaruhi oleh motivasi dan masyarakat tersebut. Penelitian ini bertujuan untuk: (1) Mengetahui signifikansi pengaruh faktor-faktor motivasi, pengetahuan, dan faktor kepemimpinan tokoh masyarakat bersama aparat pernerintah dalam peningkatan kualitas permukiman di KPKP; (2) Untuk mendapatkon model manajemen pembangunan permukiman yang partisipatif. Sampel penelitian sebanyak 370 orang yang ditarik secara proporsional cluster random sampling sederhana dan 8704 kepala keluarga di Kelurahan Lere, Kamonji, Besusu Barat, dan Kelurahan Lolu Utara (Kawasan Pusat Kota Palu). Data dikumpulkan dengan memakal teknik observasi, angket, interviu dan dokumentasi. Data dianalisis dengan teknik statistik deskriptif dan inferensial. Hasil penelitian menunjukkan bahwa tingkat partisipasi masyarakat dalam pelaksanaan peningkatan kualitas permukiman di KPKP cukup balk. Cukup baiknya tingkat pailisipasi ml disebabkan oleh tujuh faktor, yaitu: tingkat keamanan sebesar 69 persen, intensitas berinteraksi sosial sebesar 79 persen, kebutuhan prasarana dan sarana permukiman sebesar 52 persen, penghargaan sebesar 94 persen. kesempatan menerapkan kemampuan 65 persen, tingkat pengetahuan 98 persen, Jan faktor kepemimpinan sebesar 27 persen
3-Branes and Uniqueness of the Salam-Sezgin Vacuum
We prove the uniqueness of the supersymmetric Salam-Sezgin
(Minkowski)_4\times S^2 ground state among all nonsingular solutions with a
four-dimensional Poincare, de Sitter or anti-de Sitter symmetry. We construct
the most general solutions with an axial symmetry in the two-dimensional
internal space, and show that included amongst these is a family that is
non-singular away from a conical defect at one pole of a distorted 2-sphere.
These solutions admit the interpretation of 3-branes with negative tension.Comment: Latex, 12 pages; typos corrected, discussion of brane tensions
amende
External Inversion, Internal Inversion, and Reflection Invariance
Having in mind that physical systems have different levels of structure we
develop the concept of external, internal and total improper Lorentz
transformation (space inversion and time reversal). A particle obtained from
the ordinary one by the application of internal space inversion or time
reversal is generally a different particle. From this point of view the
intrinsic parity of a nuclear particle (`elementary particle') is in fact the
external intrinsic parity, if we take into account the internal structure of a
particle. We show that non-conservation of the external parity does not
necessarily imply non-invariance of nature under space inversion. The
conventional theory of beta-decay can be corrected by including the internal
degrees of freedom to become invariant under total space inversion, though not
under the external one.Comment: 15 pages. An early proposal of "mirror matter", published in 1974.
This is an exact copy of the published paper. I am posting it here because of
the increasing interest in the "exact parity models" and its experimental
consequence
Underground Phased Arrays and Beamforming Applications
This chapter presents a framework for adaptive beamforming in underground communication. The wireless propagation is thoroughly analyzed to develop a model using the soil moisture as an input parameter to provide feedback mechanism while enhancing the system performance. The working of array element in the soil is analyzed. Moreover, the effect of soil texture and soil moisture on the resonant frequency and return loss is studied in detail. The wave refraction from the soilâair interface highly degrades the performance of the system. Furthermore, to beam steering is done to achieve high gain for lateral component improving the UG communication. The angle enhancing the lateral wave depends upon dielectric properties and usually ranges from 0â to 16â. These dielectric properties change with the change in soil moisture and soil texture. It is shown from the experiments that optimal UG lateral angle is high at lower soil moisture readings and decreases with decrease in soil moisture. A planar structure of antenna array and different techniques for optimization are proposed for enhanced soil moisture adaptive beamforming. UG channel impulse response is studied from the beamforming aspect to identify the components of EM waves propagating through the soil. An optimum steering method for beamforming is presented which adapts to the changing values of soil moisture. Finally, the limitations of UG beamforming are presented along with the motivation to use it
- âŠ