3,495 research outputs found

    CP Nonconservation in e+ettˉge^+e^-\to t\bar tg

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    CP violation effects in e+ettˉge^+ e^- \to t\bar tg are examined. CP-odd, TnT_n-odd and TnT_n-even observables can both be used to extract information on the real and imaginary parts of Feynman amplitudes. Two Higgs doublet model with CP violating phase from neutral Higgs exchange is used to estimate possible effects.Comment: 9 pages, 4 Figures, Late

    Large Tree Level CP Violation in e+ettˉH0e^+e^-\to t\bar{t}H^0 in The Two Higgs Doublet Model

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    We find a large CP violation effect within the Two-Higgs-Doublet-Model for the reaction e+ettˉH0e^+e^-\to t\bar{t}H^0 at future linear colliders. The CP-asymmetry arises already at the tree level as a result of interference between diagrams with H0H^0 emission from tt (and tˉ\bar{t}) and its emission from a Z0Z^0 and can be about 10--20\%. In the best case one needs a few hundred ttˉH0t\bar{t}H^0 events to observe CP violation at the 3σ\sigma level.Comment: UU encoded tar compressed tex file with postscript figure

    Asymptotically Free Non-Abelian Gauge Theories With Fermions and Scalars As Alternatives to QCD

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    In this paper we construct non-Abelian gauge theories with fermions and scalars that nevertheless possess asymptotic freedom.The scalars are taken to be in a chiral multiplet transforming as (2,2)(2,2) under SU(2)LSU(2)RSU(2)_L\otimes SU(2)_R and transforming as singlets under the colour SU(3) group. We consider two distinct scenarios, one in which the additional scalars are light and another in which they are heavier than half the Z-boson mass. It is shown that asymptotic freedom is obtained without requiring that all additional couplings keep fixed ratios with each other. It is also shown that both scenarios can not be ruled out by what are considered standard tests of QCD like R- parameter, g-2 for muons or deep inelastic phenomena. The light mass scenario is however ruled out by high precision Z-width data (and only by that one data).The heavy mass scenario is still viable and is shown to naturally pass the test of flavour changing neutral currents. It also is not ruled out by precision electroweak oblique parameters. Many distinctive experimental signatures of these models are also discussed.Comment: 37 pages in LATEX with 10 fig

    An Image Based Approach of IRIS Recognition for Person Identification using Segmentation Algorithm

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    A biometric system gives automatic identification of an individual based on a unique feature or characteristic possessed by the individual. Iris recognition system is regarded as the most reliable and accurate biometric identification system available. Also, Iris recognition is considered to be the most reliable and accurate biometric identification system present. Iris recognition system captures an image of an individual’s eye, the iris in the image is then meant for the segmentation and normalization for extracting its features. The performance of iris recognition systems mainly depends on the segmentation. Segmentation is used for the localization of the correct iris region in the particular region of an eye and it should be done accurately and correctly to remove the eyelids, eyelashes, reection and pupil noises present in iris region. Iris images are selected from the Database, then the iris and pupil boundary is detected from rest of the eye image,by removing the noises. The segmented iris region was normalized to compress the dimensional inconsistencies between two iris regions by using Then the features of the iris were encoded by convolving the normalized iris. The Hamming distance was chosen as a matching metric parameter, which gave the measure of how many bits disagreed between the templates of the iris

    Transverse Tau Polarization in Decays of the Top and Bottom Quarks in the Weinberg Model of CP Non-conservation

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    We show that the transverse polarization asymmetry of the τ\tau-lepton in the decay tbτνt\rightarrow b \tau \nu is extremely sensitive to CP violating phases arising from the charged Higgs exchange in the Weinberg model of CP non-conservation. Qualitatively, the polarization asymmetries are enhanced over rate or energy asymmetries by a factor of mtmτO(100)\approx {m_t\over m_\tau}\approx O(100). Thus for optimal values of the parameters the method requires 104\approx 10^4 top pairs to be observable rather than 10710^7 needed for rate or energy asymmetries. We also examine τ\tau polarization in b decays via bcντb \rightarrow c \nu \tau and find that it can also be very effective in constraining the CP violation parameters of the extended Higgs sector.Comment: 11,1 figure, SLAC-PUB-608

    Service Recommendation System using Social User’s Rating Behaviors

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    The research communities of information retrieval, machine learning and data mining are recently started to paying attention towards Service recommendation systems. Traditional service recommendation algorithms are often based on batch machine learning methods which are having certain critical limitations, e.g., mostly systems are so costly also new user needs to pay the certain cost for new login, can’t capture the changes of user preferences over time. So that to overcome from that problem it is important to make service recommendation system more flexible for real world online applications where data arrives sequentially and user preferences may change randomly and dynamically. This system present a new website of online social recommendation on the basis of online graph regularized user preference learning (OGRPL), which incorporates both collaborative user-services relationship as well as service content features into an unified preference learning process. Also provide aggregated services in only one application (social networking) which increases user’s interest towards the services. This system also provides security about subscribed services as well as documents/photos on online social network application. This system will utilizes services like Education, adventure, Home Services, Hotels & Travel, Restaurants and Shopping

    Shear flow induced isotropic to nematic transition in a suspension of active filaments

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    We study the effects of externally applied shear flow on a model of suspensions of motors and filaments, via the equations of active hydrodynamics [PRL {\bf 89} (2002) 058101; {\bf 92} (2004) 118101]. In the absence of shear, the orientationally ordered phase of {\it both} polar and apolar active particles is always unstable at zero-wavenumber. An imposed steady shear large enough to overcome the active stresses stabilises both apolar and moving polar phases. Our work is relevant to {\it in vitro} studies of active filaments, the reorientation of endothelial cells subject to shear flow and shear-induced motility of attached cells.Comment: 8 pages, 4 figures submitted to Europhysics Letter

    Role of Charm Factory in Extracting CKM-Phase Information via B --> DK

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    In this paper we study the impact of data that can be obtained from a Charm Factory on the determination of the CKM parameter gamma from decays of the form B -> D0 K where the D0 decays to specific inclusive and exclusive final states. In particular, for each exclusive final state ff, the charm factory can determine the strong phase difference between D0-> f and D0-bar -> f by exploiting correlations in psi(3770)-> D0 D0-bar. This provides crucial input to the determination of gamma via the interference of B+- -> K+- D0 -> f with B+- -> K+- D0-bar -> f. We discuss how the method may be generalized to inclusive final states and illustrate with a toy model how such methods may offer one of the best means to determine gamma with 10^8-10^9 B-mesons.Comment: 12 pages, 7 figures, Version 2: Fixed typos; add reference; Version 3: fixed latex glitc
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