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Chiral corrections in electroweak processes with heavy mesonsDec 27 2002The effective theory based on combined chiral and heavy quark symmetry (HHChPT) is applied to D meson decays. The predictions for several flavor changing neutral current rare radiative charm decays are given both in the Standard Model as well as for the ... More

Cesium bright matter-wave solitons and soliton trainsFeb 08 2019A setup for studying bright matter-wave solitons of a cesium Bose-Einstein condensate (BEC) is presented. Production of a single soliton is demonstrated and dependence of soliton atom number on the interatomic interaction is studied. Formation of soliton ... More

Representations of orbifold groupoidsSep 03 2007Oct 11 2007Orbifold groupoids have been recently widely used to represent both effective and ineffective orbifolds. We show that every orbifold groupoid can be faithfully represented on a continuous family of finite dimensional Hilbert spaces. As a consequence we ... More

Penguin pollution estimates relevant for phi_2/alpha extractionDec 31 2006Aug 16 2007A review of methods to extract the standard CKM unitarity triangle angle alpha is provided. The sizes of related theoretical errors are reviewed.

Determining alpha and gamma - theoryOct 27 2004In this short review presented at FPCP04, Daegu, Korea, we discuss methods leading to determinations of alpha and gamma with practically no theoretical error. The remaining theoretical errors due to isospin breaking, neglecting of electroweak penguins ... More

The case for measuring gamma preciselyDec 30 2010We first review the methods for determining gamma from B->D K decays that appeared after CKM 2008. We then discuss the theoretical errors in gamma extraction. The errors due to neglected D-Dbar and B_{d,s}-Bbar_{d,s} mixing can be avoided by including ... More

Groupoid representations and modules over the convolution algebrasJun 11 2008The classical Serre-Swan's theorem defines a bijective correspondence between vector bundles and finitely generated projective modules over the algebra of continuous functions on some compact Hausdorff topological space. We extend these results to obtain ... More

Predictions for sin 2(beta/phi_1)_eff in b->s penguin dominated modesJul 09 2007Sep 19 2007We provide a review of predictions for sin 2beta_eff in b->s penguin dominated modes based on 1/m_b expansion and/or SU(3) flavor symmetry. The experimental results are consistently lower than the theoretical predictions. In order to interpret whether ... More

Bad-Metallic Behavior of Doped Mott InsulatorsDec 02 2015Dec 16 2015Employing Nernst-Einstein decomposition $\sigma=e^2\chi_c D$ of the conductivity $\sigma$ onto charge susceptibility (compressibility) $\chi_c$ and diffusion constant $D$, we argue that the bad-metallic behavior of $\sigma$ in the regime of high temperatures ... More

Flipping t tbar asymmetries at the Tevatron and the LHCMay 21 2012We show that the charge asymmetry in t tbar production at the LHC, A_C, and the forward-backward asymmetry at the Tevatron, A_FB, are in general not tightly correlated. They can even have opposite signs, if the underlying new physics (NP) model is general ... More

Predictions for b -> ssdbar, ddsbar decays in the SM and with new physicsAug 21 2009The b -> ssdbar and b -> ddsbar decays are highly suppressed in the SM, and are thus good probes of new physics (NP) effects. We discuss in detail the structure of the relevant SM effective Hamiltonian pointing out the presence of nonlocal contributions ... More

Two component dark matterOct 23 2008Apr 21 2009We explain the PAMELA positron excess and the PPB-BETS/ATIC e+ + e- data using a simple two component dark matter model (2DM). The two particle species in the dark matter sector are assumed to be in thermal equilibrium in the early universe. While one ... More

Donor Retention in Online Crowdfunding Communities: A Case Study of DonorsChoose.orgMar 09 2015Online crowdfunding platforms like DonorsChoose.org and Kickstarter allow specific projects to get funded by targeted contributions from a large number of people. Critical for the success of crowdfunding communities is recruitment and continued engagement ... More

The ultimate theoretical error on gamma from B -> D K decaysAug 26 2013The angle gamma of the standard CKM unitarity triangle can be determined from B -> D K decays with a very small irreducible theoretical error, which is only due to second-order electroweak corrections. We study these contributions and estimate that their ... More

Defining and Evaluating Network Communities based on Ground-truthMay 28 2012Nov 06 2012Nodes in real-world networks organize into densely linked communities where edges appear with high concentration among the members of the community. Identifying such communities of nodes has proven to be a challenging task mainly due to a plethora of ... More

On the Poisson equation for Metropolis-Hastings chainsNov 23 2015Feb 26 2017This paper defines an approximation scheme for a solution of the Poisson equation of a geometrically ergodic Metropolis-Hastings chain $\Phi$. The approximations give rise to a natural sequence of control variates for the ergodic average $S_k(F)=(1/k)\sum_{i=1}^{k} ... More

node2vec: Scalable Feature Learning for NetworksJul 03 2016Prediction tasks over nodes and edges in networks require careful effort in engineering features used by learning algorithms. Recent research in the broader field of representation learning has led to significant progress in automating prediction by learning ... More

Modeling Social Networks with Node Attributes using the Multiplicative Attribute Graph ModelJun 24 2011Networks arising from social, technological and natural domains exhibit rich connectivity patterns and nodes in such networks are often labeled with attributes or features. We address the question of modeling the structure of networks where nodes have ... More

Dark Matter attempts for CoGeNT and DAMAJun 30 2011Recently, the CoGeNT collaboration presented a positive signal for an annual modulation in their data set. In light of the long standing annual modulation signal in DAMA/LIBRA, we analyze the compatibility of both of these signal within the hypothesis ... More

Computing the Stereo Matching Cost with a Convolutional Neural NetworkSep 15 2014Oct 20 2015We present a method for extracting depth information from a rectified image pair. We train a convolutional neural network to predict how well two image patches match and use it to compute the stereo matching cost. The cost is refined by cross-based cost ... More

Stereo Matching by Training a Convolutional Neural Network to Compare Image PatchesOct 20 2015May 18 2016We present a method for extracting depth information from a rectified image pair. Our approach focuses on the first stage of many stereo algorithms: the matching cost computation. We approach the problem by learning a similarity measure on small image ... More

SNAP: A General Purpose Network Analysis and Graph Mining LibraryJun 24 2016Large networks are becoming a widely used abstraction for studying complex systems in a broad set of disciplines, ranging from social network analysis to molecular biology and neuroscience. Despite an increasing need to analyze and manipulate large networks, ... More

Latent Multi-group Membership Graph ModelMay 21 2012We develop the Latent Multi-group Membership Graph (LMMG) model, a model of networks with rich node feature structure. In the LMMG model, each node belongs to multiple groups and each latent group models the occurrence of links as well as the node feature ... More

Structure and Overlaps of Communities in NetworksMay 28 2012Sep 25 2012One of the main organizing principles in real-world social, information and technological networks is that of network communities, where sets of nodes organize into densely linked clusters. Even though detection of such communities is of great interest, ... More

Multiplicative Attribute Graph Model of Real-World NetworksSep 17 2010Apr 14 2011Large scale real-world network data such as social and information networks are ubiquitous. The study of such social and information networks seeks to find patterns and explain their emergence through tractable models. In most networks, and especially ... More

Planetary-Scale Views on an Instant-Messaging NetworkMar 06 2008We present a study of anonymized data capturing a month of high-level communication activities within the whole of the Microsoft Messenger instant-messaging system. We examine characteristics and patterns that emerge from the collective dynamics of large ... More

Pseudo-Casimir force in confined nematic polymersSep 08 2000We investigate the pseudo-Casimir force in a slab of material composed of nematically ordered long polymers. We write the total mesoscopic energy together with the constraint connecting the local density and director fluctuations and evaluate the corresponding ... More

Asymptotic variance for Random walk Metropolis chains in high dimensions: logarithmic growth via the Poisson equationJul 26 2017Feb 07 2019There are two ways of speeding up MCMC algorithms: (1) construct more complex samplers that use gradient and higher order information about the target and (2) design a control variate to reduce the asymptotic variance. While the efficiency of (1) as a ... More

Nonparametric Multi-group Membership Model for Dynamic NetworksNov 08 2013Relational data-like graphs, networks, and matrices-is often dynamic, where the relational structure evolves over time. A fundamental problem in the analysis of time-varying network data is to extract a summary of the common structure and the dynamics ... More

B^\pm -> D K^\pm with direct CP violation in charmDec 01 2012Dec 20 2012We investigate the implications of direct CP violation (CPV) on the determination of the unitarity triangle angle \gamma\ from B -> DK decays. We show that \gamma\ can still be extracted even with the inclusion of direct CPV in charm if (i) at least one ... More

Continuous Flavor Symmetries and the Stability of Asymmetric Dark MatterAug 17 2014Generically, the asymmetric interactions in asymmetric dark matter (ADM) models lead to decaying DM. We show that, for ADM that carries nonzero baryon number, the continuous flavor symmetries that generate the flavor structure in the quark sector also ... More

From Amateurs to Connoisseurs: Modeling the Evolution of User Expertise through Online ReviewsMar 18 2013Recommending products to consumers means not only understanding their tastes, but also understanding their level of experience. For example, it would be a mistake to recommend the iconic film Seven Samurai simply because a user enjoys other action movies; ... More

Discovering Social Circles in Ego NetworksOct 30 2012Jan 10 2013People's personal social networks are big and cluttered, and currently there is no good way to automatically organize them. Social networking sites allow users to manually categorize their friends into social circles (e.g. 'circles' on Google+, and 'lists' ... More

Image Labeling on a Network: Using Social-Network Metadata for Image ClassificationJul 16 2012Large-scale image retrieval benchmarks invariably consist of images from the Web. Many of these benchmarks are derived from online photo sharing networks, like Flickr, which in addition to hosting images also provide a highly interactive social community. ... More

On the Poisson equation for Metropolis-Hastings chainsNov 23 2015This paper defines an approximation scheme for a solution of the Poisson equation of a geometrically ergodic Metropolis-Hastings chain $\Phi$. The approximations give rise to a natural sequence of control variates for the ergodic average $S_k(F)=(1/k)\sum_{i=1}^{k} ... More

On the Convexity of Latent Social Network InferenceOct 26 2010In many real-world scenarios, it is nearly impossible to collect explicit social network data. In such cases, whole networks must be inferred from underlying observations. Here, we formulate the problem of inferring latent social networks based on network ... More

A Simple Number Theoretic ResultJul 28 2012We derive an interesting congruence relation motivated by an Indian Olympiad problem. We give three different proofs of the theorem and mention a few interesting related results.

The Bursty Dynamics of the Twitter Information NetworkMar 11 2014In online social media systems users are not only posting, consuming, and resharing content, but also creating new and destroying existing connections in the underlying social network. While each of these two types of dynamics has individually been studied ... More

Discovering Dark Matter Through Flavor Violation at the LHCJul 04 2011We show that the discovery channel for dark matter (DM) production at colliders can be through flavor violating interactions resulting in a novel signature of a single top and large missing transverse energy. We discuss several examples where the production ... More

Binomial Symbols and Prime ModuliSep 07 2012We try to improve a problem asked in an Indian Math Olympiad. We give a brief overview of the work done in Saikia and Vogrinc (2011) and Saikia and Vogrinc where the authors have found a periodic sequence and the length of its period, all inspired from ... More

Two body B decays with isosinglet final states in SCETJan 26 2006Aug 23 2006Expressions for decay amplitudes of B0, B- and Bs mesons to two light pseudoscalar or vector mesons, including isosinglet mesons eta, eta', omega, phi, are obtained using Soft Collinear Effective Theory at LO in 1/mb. These are then used to predict unmeasured ... More

Phenomenology of Dark Matter annihilation into a long-lived intermediate stateMar 18 2009Jul 13 2009We propose a scenario where Dark Matter (DM) annihilates into an intermediate state which travels a distance $\lambda \equiv v/\Gamma$ on the order of galactic scales and then decays to Standard Model (SM) particles. The long lifetime disperses the production ... More

CP Asymmetries in B->K pi, K*pi, rho K DecaysJan 05 2010Mar 31 2010We show that ratios of tree and penguin amplitudes in B-> K*pi and B->rho K are two to three times larger than in B-> K pi. This allows for considerably larger CP asymmetries in the former processes than the 10% asymmetry measured in B0 -> K+pi-. We study ... More

Unitarity triangle angles from penguin-dominated B meson decaysMay 01 2011In this time of transition to a new generation of quark flavor experiments we review both the theoretical and the experimental progress on the determination of unitarity triangle angles from penguin-dominated B decays. This summarizes the activities of ... More

Phase behaviour of colloidal assemblies on 2D corrugated substratesApr 24 2012We investigate - with Monte Carlo computer simulations - the phase behaviour of dimeric colloidal molecules on periodic substrates with square symmetry. The molecules are formed in a two-dimensional suspension of like charged colloids subject to periodic ... More

Colloidal ionic complexes on periodic substrates: ground state configurations and pattern switchingFeb 08 2011We theoretically and numerically studied ordering of "colloidal ionic clusters" on periodic substrate potentials as those generated by optical trapping. Each cluster consists of three charged spherical colloids: two negatively and one positively charged. ... More

Information Diffusion and External Influence in NetworksJun 06 2012Social networks play a fundamental role in the diffusion of information. However, there are two different ways of how information reaches a person in a network. Information reaches us through connections in our social networks, as well as through the ... More

I'll Be Back: On the Multiple Lives of Users of a Mobile Activity Tracking ApplicationFeb 25 2018Mobile health applications that track activities, such as exercise, sleep, and diet, are becoming widely used. While these activity tracking applications have the potential to improve our health, user engagement and retention are critical factors for ... More

Higgs portal, fermionic dark matter, and a Standard Model like Higgs at 125 GeVMar 09 2012Jul 09 2012We show that fermionic dark matter (DM) which communicates with the Standard Model (SM) via the Higgs portal is a viable scenario, even if a SM-like Higgs is found at around 125 GeV. Using effective field theory we show that for DM with a mass in the ... More

Astrophysics independent bounds on the annual modulation of dark matter signalsMay 01 2012We show how constraints on the time integrated event rate from a given dark matter (DM) direct detection experiment can be used to set a stringent constraint on the amplitude of the annual modulation signal in another experiment. The method requires only ... More

Testing for new physics in singly Cabibbo suppressed D decaysApr 16 2012We devise tests for a new physics origin of the recently measured direct CP violation in singly Cabibbo suppressed D decays. The tests take the form of sum rules for the CP asymmetries in various D decays. They are based on the fact that within the standard ... More

QCD Corrections to Flavor Changing Neutral Coupling Mediated Rare Top Quark DecaysJul 15 2010Aug 04 2010Recently we have presented an analysis of flavor changing neutral coupling mediated radiative top quark decays at next-to-leading order in QCD. In the present paper we provide the details of the calculation of QCD corrections to t-> q gamma and t-> q ... More

Flavor Changing Neutral Coupling Mediated Radiative Top Quark Decays at Next-to-Leading Order in QCDApr 05 2010We compute the branching ratios for the rare top quark decays t to c gamma and t to c Z mediated by effective flavor changing neutral couplings at the next-to-leading order in QCD including the effects due to operator mixing. After re-suming contributions ... More

Large-scale Analysis of Counseling Conversations: An Application of Natural Language Processing to Mental HealthMay 14 2016Aug 14 2016Mental illness is one of the most pressing public health issues of our time. While counseling and psychotherapy can be effective treatments, our knowledge about how to conduct successful counseling conversations has been limited due to lack of large-scale ... More

Structure and Dynamics of Information Pathways in Online MediaDec 06 2012Diffusion of information, spread of rumors and infectious diseases are all instances of stochastic processes that occur over the edges of an underlying network. Many times networks over which contagions spread are unobserved, and such networks are often ... More

Governance in Social Media: A case study of the Wikipedia promotion processApr 20 2010Social media sites are often guided by a core group of committed users engaged in various forms of governance. A crucial aspect of this type of governance is deliberation, in which such a group reaches decisions on issues of importance to the site. Despite ... More

Ground states of colloidal molecular crystals on periodic substratesFeb 01 2008Two dimensional suspensions of spherical colloids subject to periodic external fields exhibit a rich variety of molecular crystalline phases. We study in simulations the ground state configurations of dimeric and trimeric systems, that are realized on ... More

Effects of initial axion production and photon--axion oscillation on type Ia supernova dimmingApr 18 2002Jul 17 2002Recently, Csaki, Kaloper and Terning (CKT) suggested that axion-photon oscillation in the intergalactic medium can explain the observed dimming of distant type Ia supernovae. This mechanism works only if the initial axion flux is much smaller than the ... More

Light quark Yukawa couplings from Higgs kinematicsJun 30 2016Aug 16 2016We show that the normalized Higgs production $p_T$ and $y_h$ distributions are sensitive probes of Higgs couplings to light quarks. For up and/or down quark Yukawa couplings comparable to the SM $b$ quark Yukawa the $\bar u u$ or $\bar d d$ fusion production ... More

Minimal Models for Dark Matter and the Muon g-2 AnomalyMar 30 2018Jul 08 2018We construct models with minimal field content that can simultaneously explain the muon g-2 anomaly and give the correct dark matter relic abundance. These models fall into two general classes, whether or not the new fields couple to the Higgs. For the ... More

Cultural Shift or Linguistic Drift? Comparing Two Computational Measures of Semantic ChangeJun 09 2016Sep 24 2016Words shift in meaning for many reasons, including cultural factors like new technologies and regular linguistic processes like subjectification. Understanding the evolution of language and culture requires disentangling these underlying causes. Here ... More

Modeling Individual Cyclic Variation in Human BehaviorDec 15 2017Apr 20 2018Cycles are fundamental to human health and behavior. However, modeling cycles in time series data is challenging because in most cases the cycles are not labeled or directly observed and need to be inferred from multidimensional measurements taken over ... More

Modeling Interdependent and Periodic Real-World Action SequencesFeb 26 2018Mobile health applications, including those that track activities such as exercise, sleep, and diet, are becoming widely used. Accurately predicting human actions is essential for targeted recommendations that could improve our health and for personalization ... More

Online Actions with Offline Impact: How Online Social Networks Influence Online and Offline User BehaviorDec 09 2016Dec 16 2016Many of today's most widely used computing applications utilize social networking features and allow users to connect, follow each other, share content, and comment on others' posts. However, despite the widespread adoption of these features, there is ... More

Inferring Networks of Diffusion and InfluenceJun 01 2010Oct 23 2011Information diffusion and virus propagation are fundamental processes taking place in networks. While it is often possible to directly observe when nodes become infected with a virus or adopt the information, observing individual transmissions (i.e., ... More

Updated bounds on CP asymmetries in $B^0 \to η' K_S$ and $B^0 \to π^0 K_S$Aug 07 2006Oct 27 2006New rate measurements of $B^0$ decays into $\pi^0\pi^0, \pi^0\eta, \pi^0\eta', \eta\eta, \eta\eta', \eta'\eta'$ and $K^+ K^-$ are used in conjunction with flavor SU(3) to constrain the coefficients $S$ and $C$ of $\sin\Delta mt$ and $\cos\Delta mt$ in ... More

Constraints on CP-violating Higgs couplings to the third generationOct 04 2013Nov 27 2013Discovering CP-violating effects in the Higgs sector would constitute an indisputable sign of physics beyond the Standard Model. We derive constraints on the CP-violating Higgs-boson couplings to top and bottom quarks as well as to tau leptons from low-energy ... More

Flavor Violating Higgs DecaysSep 06 2012Aug 14 2015We study a class of nonstandard interactions of the newly discovered 125 GeV Higgs-like resonance that are especially interesting probes of new physics: flavor violating Higgs couplings to leptons and quarks. These interaction can arise in many frameworks ... More

Size of direct CP violation in singly Cabibbo-suppressed D decaysNov 21 2011Sep 16 2015The first experimental evidence for direct CP violation in charm-quark decays has recently been presented by the LHCb collaboration in the difference between the D -> K+ K- and D -> pi+ pi- time-integrated CP asymmetries. We estimate the size of the effects ... More

Community Detection in Networks with Node AttributesJan 28 2014Community detection algorithms are fundamental tools that allow us to uncover organizational principles in networks. When detecting communities, there are two possible sources of information one can use: the network structure, and the features and attributes ... More

Review of new physics effects in t-tbar productionJul 26 2011Both CDF and DO report a forward-backward asymmetry in t-tbar production that is above the standard model prediction. We review new physics models that can give a large forward backward asymmetry in t-tbar production at the Tevatron and the constraints ... More

Graph Evolution: Densification and Shrinking DiametersMar 27 2006Jan 28 2007How do real graphs evolve over time? What are ``normal'' growth patterns in social, technological, and information networks? Many studies have discovered patterns in static graphs, identifying properties in a single snapshot of a large network, or in ... More

How to test for mass degenerate Higgs resonancesJan 02 2013Apr 25 2013The Higgs-like signal observed at the LHC could be due to several mass degenerate resonances. We show that the number of resonances is related to the rank of a "production and decay" matrix, $R_{if}$. Each entry in this matrix contains the observed rate ... More

Smoking Guns for On-Shell New Physics at the LHCSep 09 2008Using Tevatron bounds we derive upper limits on the LHC Higgs production rate under the assumption that no beyond the Standard Model (BSM) particles are being produced near their mass shell. A violation of these limits would constitute a smoking gun for ... More

Correlated bounds on CP asymmetries in $B^0 \to η' K_S$Mar 29 2004Jun 25 2004Flavor SU(3) is used to constrain the coefficients of $\sin\Delta mt$ and $\cos\Delta mt$ in the time-dependent CP asymmetry of $B^0 \to \eta' K_S$. Correlated bounds in the $(S_{\eta' K}, C_{\eta' K})$ plane are derived, by using recent rate measurements ... More

Modeling Information Propagation with Survival TheoryMay 15 2013Networks provide a skeleton for the spread of contagions, like, information, ideas, behaviors and diseases. Many times networks over which contagions diffuse are unobserved and need to be inferred. Here we apply survival theory to develop general additive ... More

Predicting Positive and Negative Links in Online Social NetworksMar 11 2010We study online social networks in which relationships can be either positive (indicating relations such as friendship) or negative (indicating relations such as opposition or antagonism). Such a mix of positive and negative links arise in a variety of ... More

Global interpretation of direct Dark Matter searches after CDMS-II resultsDec 22 2009Mar 02 2010We perform a global fit to data from Dark Matter (DM) direct detection experiments, including the recent CDMS-II results. We discuss possible interpretations of the DAMA annual modulation signal in terms of spin-independent and spin-dependent DM-nucleus ... More

The Role of Social Networks in Online Shopping: Information Passing, Price of Trust, and Consumer ChoiceApr 05 2011While social interactions are critical to understanding consumer behavior, the relationship between social and commerce networks has not been explored on a large scale. We analyze Taobao, a Chinese consumer marketplace that is the world's largest e-commerce ... More

Learning Attitudes and Attributes from Multi-Aspect ReviewsOct 15 2012Oct 31 2012The majority of online reviews consist of plain-text feedback together with a single numeric score. However, there are multiple dimensions to products and opinions, and understanding the `aspects' that contribute to users' ratings may help us to better ... More

Inferring Networks of Substitutable and Complementary ProductsJun 29 2015In a modern recommender system, it is important to understand how products relate to each other. For example, while a user is looking for mobile phones, it might make sense to recommend other phones, but once they buy a phone, we might instead want to ... More

B-->pi and B-->K transitions in standard and quenched chiral perturbation theoryOct 25 2002Feb 14 2003We study the effects of chiral logs on the heavy-->light pseudoscalar meson transition form factors by using standard and quenched chiral perturbation theory combined with the static heavy quark limit. The resulting expressions are used to indicate the ... More

Diachronic Word Embeddings Reveal Statistical Laws of Semantic ChangeMay 30 2016Sep 26 2016Understanding how words change their meanings over time is key to models of language and cultural evolution, but historical data on meaning is scarce, making theories hard to develop and test. Word embeddings show promise as a diachronic tool, but have ... More

Citing for High ImpactApr 20 2010The question of citation behavior has always intrigued scientists from various disciplines. While general citation patterns have been widely studied in the literature we develop the notion of citation projection graphs by investigating the citations among ... More

Photoinduced Fano-resonance of coherent phonons in zincNov 02 2006Utilizing femtosecond optical pump-probe technique, we have studied transient Fano-resonance in zinc. At high excitation levels the Fourier spectrum of the coherent E$_{2g}$ phonon exhibits strongly asymmetric line shape, which is well modeled by the ... More

Design principles for super selectivity using multivalent interactionsAug 03 2016Multivalent particles have the ability to form multiple bonds to a substrate. Hence, a multivalent interaction can be strong, even if the individual bonds are weak. However, much more interestingly, multivalency greatly increases the sensitivity of the ... More

Carrier relaxation dynamics in high temperature superconductorsJul 17 2002In this report we review recent experimental results on photoexcited carrier relaxation dynamics on high temperature superconductors (HTSC) probed by a femtosecond time-resolved optical spectroscopy, and compare the results with the data obtained on quasi ... More

Probing anomalous tWb interactions with rare B decaysSep 11 2011Precision studies of top quark properties are currently underway at the LHC and Tevatron colliders with the prospect of probing anomalous t-W -b interactions. In the mean time, recent experimental results for the B_{d,s} - \bar{B}_{d,s} oscillation observables, ... More

Interplay of t --> b W Decay and B_q Meson Mixing in Minimal Flavor Violating ModelsFeb 21 2011Jul 06 2011Precise measurements of the top quark decay properties at hadron colliders offer interesting new possibilities of testing the standard model. At the same time, recent intriguing experimental results concerning CP violation in the B_d and B_s systems have ... More

New physics in t-> b W decay at next-to-leading order in QCDOct 12 2010Nov 12 2010We consider contributions of non-standard tbW effective operators to the decay of an unpolarized top quark into a bottom quark and a W gauge boson at next-to-leading order in QCD. We find that the dipole operator O_{LR} contribution to the transverse-plus ... More

Signatures of NP models in top FCNC decay t --> c(u) l+ l-Dec 01 2008Feb 24 2009Among other roles the LHC will play a role of the top "factory" and it will give us unique possibility to study new physics signatures in different ways. Many scenarios of new physics allow top quark FCNC decays. Using most general model independent Lagrangian ... More

On the annual modulation signal in dark matter direct detectionDec 07 2011Feb 14 2012We derive constraints on the annual modulation signal in Dark Matter (DM) direct detection experiments in terms of the unmodulated event rate. A general bound independent of the details of DM distribution follows from the assumption that the motion of ... More

The Effect of $D-\bar D$ Mixing on the Measurement of $γ$ in $B\to D K$ DecaysMay 31 2005$D-\bar D$ mixing is the source of the largest theoretical uncertainty in the extraction of $\gamma$ from $B\to D K$ decays. In the Standard Model, the mixing can have a rate close to its current experimental upper bound and is CP-conserving to an excellent ... More

Integrating in the Higgs Portal to Fermion Dark MatterJun 12 2015Jun 23 2015Fermion dark matter (DM) interacting with the standard model through a Higgs portal requires non-renormalizable operators, signaling the presence of new mediator states at the electroweak scale. Collider signatures that involve the mediators are a powerful ... More

Network Lasso: Clustering and Optimization in Large GraphsJul 01 2015Convex optimization is an essential tool for modern data analysis, as it provides a framework to formulate and solve many problems in machine learning and data mining. However, general convex optimization solvers do not scale well, and scalable solvers ... More

Mining Missing Hyperlinks from Human Navigation Traces: A Case Study of WikipediaMar 13 2015Hyperlinks are an essential feature of the World Wide Web. They are especially important for online encyclopedias such as Wikipedia: an article can often only be understood in the context of related articles, and hyperlinks make it easy to explore this ... More

Signed Networks in Social MediaMar 11 2010Relations between users on social media sites often reflect a mixture of positive (friendly) and negative (antagonistic) interactions. In contrast to the bulk of research on social networks that has focused almost exclusively on positive interpretations ... More

B --> pi and B --> K transitions in partially quenched chiral perturbation theoryApr 30 2003Sep 14 2003We study the properties of the B-->pi and B-->K transition form factors in partially quenched QCD by using the approach of partially quenched chiral perturbation theory combined with the static heavy quark limit. We show that the form factors change almost ... More

Light Dark Matter in the light of CRESST-IIOct 12 2011Recently the CRESST collaboration has published the long anticipated results of their direct Dark Matter (DM) detection experiment with a CaWO_4 target. The number of observed events exceeds known backgrounds at more than 4 sigma significance, and this ... More

Energy level statistics in the transition regime between integrability and chaos for systems with broken antiunitary symmetryNov 10 1997Energy spectra of a particle with mass $m$ and charge $e$ in the cubic Aharonov-Bohm billiard containing around $10^4$ consecutive levels starting from the ground state have been analysed. The cubic Aharonov-Bohm billiard is a plane billiard defined by ... More