Results for "Alejandra Valencia"

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Two-photon interference with thermal lightOct 27 2004Nov 08 2004The study of entangled states has greatly improved the basic understanding about two-photon interferometry. Two-photon interference is not the interference of two photons but the result of superposition among indistinguishable two-photon amplitudes. The ... More
Experimental study of the momentum correlation of a pseudo-thermal field in the photon counting regimeSep 29 2004Thermal (or pseudo-thermal) radiation has been recently proposed for imaging and interference types of experiments to simulate entangled states. We report an experimental study on the momentum correlation properties of a pseudo-thermal field in the photon ... More
Distant Clock Synchronization Using Entangled Photon PairsJul 26 2004We report a proof-of-principle experiment on distant clock synchronization. Besides the achievement of picosecond resolution at 3 kilometer distance, this experiment demonstrated a novel concept for high accuracy non-local timing and positioning based ... More
On the congruence subgroup problem for branch groupsMay 13 2014Jul 11 2014We answer a question of Bartholdi, Siegenthaler and Zalesskii, showing that the congruence subgroup problem for branch groups is independent of the branch action on a tree. We prove that the congruence topology of a branch group is determined by the group; ... More
Abstract commensurability and the Gupta--Sidki groupOct 01 2013Sep 13 2016We study the subgroup structure of the infinite torsion $p$-groups defined by Gupta and Sidki in 1983. In particular, following results of Grigorchuk and Wilson for the first Grigorchuk group, we show that all infinite finitely generated subgroups of ... More
Cancelation of dispersion and temporal modulation with non-entangled frequency-correlated photonsNov 29 2010Nov 30 2010The observation of the so-called dispersion cancelation (Opt. Express 17, 19244, 2009) and temporal phase modulation (Phys. Rev. Lett. 103, 163601, 2009) of paired photons is generally attributed to the presence of frequency entanglement between two frequency ... More
Remote spectral measurement using entangled photonsJul 20 2004By utilizing the frequency anticorrelation of two-photon states produced via spontaneous parametric down conversion (SPDC), the working principle of a novel remote spectrometer is demonstrated. With the help of a local scanning monochromator, the spectral ... More
Two-photon "ghost" imaging with thermal lightJul 30 2004Feb 18 2005We report the first experimental demonstration of two-photon imaging with a pseudo-thermal source. Similarly to the case of entangled states, a two-photon Gaussian thin lens equation is observed, indicating EPR type correlation in position. We introduce ... More
Entangled Two-Photon Wave Packet in a Dispersive MediumJul 26 2004We report an experimental study of group-velocity dispersion effect on an entangled two-photon wavepacket, generated via spontaneous parametric down-conversion and propagating through a dispersive medium. Even in the case of using CW laser beam for pump, ... More
Correlation control for pure and efficiently generated heralded single photonsOct 07 2014We present a detailed study on the properties of single photons generated by spontaneous parametric down conversion (SPDC) when both the spectral and spatial degrees of freedom are controlled by means of filters. Our results show that it is possible to ... More
Observation of spectral interference for any path difference in an interferometerApr 05 2014We report the experimental observation of spectral interference in a Michelson interferometer, regardless of the relationship between the temporal path difference introduced between the arms of the interferometer and the spectral width of the input pulse. ... More
Spatiotemporal correlations in entangled photons generated by spontaneous parametric down conversionApr 15 2008Sep 19 2008In most configurations aimed at generating entangled photons based on spontaneous parametric down conversion (SPDC), the generated pairs of photons are required to be entangled in only one degree of freedom. Any distinguishing information coming from ... More
Sigma to p mu+ mu-: Standard Model or New Particle?May 21 2008The HyperCP collaboration observed three events for the decay Sigma to p mu+ mu-. They suggested that new physics may be required to understand the implied decay rate and the observed dimuon invariant mass distribution. Motivated by this result, we re-examine ... More
Experimental Signatures of a Parity Violating Anomalous Coupling $g_5^Z$Apr 01 1995I discuss the experimental signatures of a parity violating but CP conserving interaction in the symmetry breaking sector of the electroweak theory.
Correlation control for pure and efficiently generated heralded single photonsOct 07 2014Jan 18 2018We present a detailed study on the properties of single photons generated by spontaneous parametric down conversion (SPDC) when both the spectral and spatial degrees of freedom are controlled by means of filters. Our results show that it is possible to ... More
Generation of indistinguishable and pure heralded single photons with tunable bandwidthDec 17 2007We describe a new scheme to fully control the joint spectrum of paired photons generated in spontaneous parametric down-conversion. We show the capability of this method to generate frequency-uncorrelated photon pairs that are pure and indistinguishable, ... More
Tunable beam displacerMay 19 2014Jan 08 2015We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are ... More
Flat affine symplectic Lie groupsFeb 05 2019We give a new characterization of flat affine manifolds in terms of an action of the Lie algebra of classical infinitesimal affine transformations on the bundle of linear frames. We prove that a left invariant flat affine symplectic connection on a connected ... More
Notes on flat pseudo-Riemannian manifoldsMar 21 2019In these notes we survey basic concepts of affine geometry and their interaction with Riemannian geometry. We give a characterization of affine manifolds which has as counterpart those pseudo-Riemannian manifolds whose Levi-Civita connection is flat. ... More
Composition of Transiting and Transiting-only super-EarthsMar 18 2011The relatively recent detections of the first three transiting super-Earths mark the beginning of a subfield within exoplanets that is both fruitful and challenging. The first step into characterizing these objects is to infer their composition given ... More
CP Violation in $Λ$ to p $π^-$: SM vs New PhysicsJun 15 2000I discuss CP violation in $\Lambda$ to p $\pi^-$ comparing the standard model expectations with what could happen in new physics scenarios. I point out that Fermilab experiment E871 is sensitive to some of these scenarios.
Long Distance Contribution to $K_L \to \ell^+ \ell^-$Nov 18 1997Feb 04 1998We revisit the calculation of the long distance contribution to $K_L \to \mu^+ \mu^-$. We discuss this process within the framework of chiral perturbation theory, and also using simple models for the $K_L \gamma^* \gamma^*$ vertex. We argue that it is ... More
Theoretical Aspects of CP Violation in Hyperon DecaysNov 05 1995I review the estimate of the CP violating asymmetry $A(\Lambda^0_-)$ within the standard model. I then review the estimate of the upper bound on this asymmetry that arises from measurements of CP violation in kaon decays.
Anomalous Gauge-Boson Couplings at Hadron SupercollidersSep 15 1992We discuss anomalous gauge boson couplings at hadron supercolliders. We review the usual description of these couplings, as well as the studies of a strongly interacting electroweak symmetry breaking sector. We present an effective field theory formulation ... More
CP violation in top-quark pair production and decayJan 06 2013As the LHC becomes a top-quark factory and enters the era of precision measurements it presents us with a unique opportunity to search for new sources of CP violation. I discuss T-odd triple product correlations and the special role they play in the search ... More
CP violation in top-quark physicsJul 27 2010In this talk I review how to search for CP violation in top-quark pair production and decay using T-odd correlations. I discuss two examples which illustrate many of the relevant features: CP violation in a heavy neutral Higgs boson; and CP violating ... More
Colour Octet Extension of 2HDMJun 09 2016In this talk we consider some aspects of the Manohar-Wise extension of the SM with a colour-octet electroweak-doublet scalar applied to 2HDM. We present theoretical constraints on the parameters of this extension to both the SM and the 2HDM and discuss ... More
Flat affine symplectic Lie groupsFeb 05 2019Mar 02 2019We give a new characterization of flat affine manifolds in terms of an action of the Lie algebra of classical infinitesimal affine transformations on the bundle of linear frames. We prove that a left invariant flat affine symplectic connection on a connected ... More
Semantic Structures for Spatially-Distributed Multi-Agent SystemsAug 23 2019Spatial constraint systems (scs) are semantic structures for reasoning about spatial and epistemic information in concurrent systems. They have been used to reason about beliefs, lies, and group epistemic behaviour inspired by social networks. They have ... More
Probing new physics with tau-leptons at the LHCJan 17 2013We discuss new physics that can show up in the $\tau^+\tau^-$ production process at the LHC but not in the dimuon or the dielectron channels. We consider three different generic possibilities: a new resonance in the Drell-Yan process in the form of a ... More
Primordial Magnetic Field Amplification from Turbulent ReheatingApr 12 2010Jul 05 2010We analyze the possibility of primordial magnetic field amplification by a stochastic large scale kinematic dynamo during reheating. We consider a charged scalar field minimally coupled to gravity. During inflation this field is assumed to be in its vacuum ... More
Deconstructing the D0-D6 systemMar 31 2009Jun 08 2009We find the complete classical moduli space of two-centered supersymmetric solutions carrying D0 and D6 brane charge in the STU model delimited by walls of marginal stability of co-dimension one. U-duality guarantees our conclusions hold for any BPS state ... More
Degenerations of 8-dimensional 2-step nilpotent Lie algebrasSep 10 2019In this work, we consider degenerations between 8-dimensional 2-step nilpotent Lie algebras over $\mathbb{C}$ and obtain the geometric classification of the variety $\mathcal{N}^2_8$.
A Hydrodynamic Approach to the Study of Anisotropic Instabilities in Dissipative Relativistic PlasmasFeb 04 2016Sep 29 2016We develop a purely hydrodynamic formalism to describe collisional, anisotropic instabilities in a relativistic plasma, that are usually described with kinetic theory tools. Our main motivation is the fact that coarse-grained models of high particle number ... More
Primordial Magnetic Helicity from Stochastic Electric CurrentsMar 05 2014We study the possibility that primordial magnetic fields generated in the transition between inflation and reheating posses magnetic helicity, $H_M$. The fields are induced by stochastic currents of scalar charged particles created during the mentioned ... More
The Boundedness of the (Sub)Bilinear Maximal Function along "non-flat" smooth curvesMar 26 2019Let $\mathcal{N}\mathcal{F}$ be the class of smooth non-flat curves near the origin and near infinity previously introduced by the second author and let $\gamma\in\mathcal{N}\mathcal{F}$. We show - via a unifying approach relative to the correspondent ... More
A quantum metric on the Cantor SpaceJul 12 2019The first author and Latr\'emoli\`ere had introduced a quantum metric (in the sense of Rieffel) on the algebra of complex-valued continuous functions on the Cantor space. We show that this quantum metric is distinct from the quantum metric induced by ... More
Implementation and characterization of a controllable dephasing channel based on coupling polarization and spatial degrees of freedom of lightOct 26 2017We present the experimental implementation and theoretical model of a controllable dephasing quantum channel using photonic systems. The channel is implemented by coupling the polarization and the spatial distribution of light, that play, in the perspective ... More
Measuring different types of transverse momentum correlations in the biphoton's Fourier planeDec 16 2015In this work, we present a theoretical and experimental study about the spatial correlations of paired photons generated by type-II spontaneous parametric down-conversion. In particular, we show how these correlations can be positive or negative depending ... More
Shaping the waveform of entangled photonsSep 12 2007We demonstrate experimentally the tunable control of the joint spectrum, i.e. waveform and degree of frequency correlations, of paired photons generated in spontaneous parametric downconversion. This control is mediated by the spatial shape of the pump ... More
Weighted generalized inverses, oblique projections and least squares problemsSep 14 2005A generalization with singular weights of Moore-Penrose generalized inverses of closed range operators in Hilbert spaces is studied using the notion of compatibility of subspaces and positive operators.
Magnetic operations: a little fuzzy physics?Jun 10 2010Dec 20 2010We examine the behaviour of charged particles in homogeneous, constant and/or oscillating magnetic fields in the non-relativistic approximation. A special role of the geometric center of the particle trajectory is elucidated. In quantum case it becomes ... More
Demonstration of a highly-sensitive tunable beam displacer with no movable elements based on the concept of weak value amplificationFeb 19 2015We report the implementation of a highly sensitive beam displacer based on the concept of weak value amplification that allows to displace the centroid of a Gaussian beam a distance much smaller than its beam width without the need to use movable optical ... More
Entangled two photon absorption cross section on the 808 nm region for the common dyes Zinc tetraphenylporphyrin and Rhodamine BNov 15 2016We report the measurement of the entangled two photon absorption cross section, $\sigma_E$, at 808 nm on organic chromophores in solution in a low photon flux regime. We performed measurements on Zinc tetraphenylporphyrin (ZnTPP) in Toluene and Rhodamine ... More
Maximal subgroups of groups of intermediate growthNov 03 2016Finding the number of maximal subgroups of infinite index of a finitely generated subgroup is a natural problem that has been solved for several classes of "geometric" groups (linear groups, hyperbolic groups, mapping class groups, etc). Here we provide ... More
Near Extremal Kerr Entropy from AdS_2 Quantum GravityAug 07 2009Aug 17 2009We analyze the asymptotic symmetries of near extremal Kerr black holes in four dimensions using the AdS_2/CFT_1 correspondence. We find a Virasoro algebra with central charge c_R=12J that is independent from the Virasoro algebra (with the same central ... More
Products of orthogonal projections and polar decompositionsNov 23 2010We characterize the sets $\XX$ of all products $PQ$, and $\YY$ of all products $PQP$, where $P,Q$ run over all orthogonal projections and we solve the problems $\arg\min\{\|P-Q\|: (P,Q) \in \cal Z\}$, for $\cal Z=\XX$ or $\YY.$ We also determine the polar ... More
Breaking away from the near horizon of extreme KerrJun 21 2019Sep 06 2019We study gravitational perturbations around the near horizon geometry of the (near) extreme Kerr black hole. By considering a consistent truncation for the metric fluctuations, we obtain a solution to the linearized Einstein equations. The dynamics is ... More
Tracing the temporal evolution of clusters in a financial stock marketNov 14 2011We propose a methodology for clustering financial time series of stocks' returns, and a graphical set-up to quantify and visualise the evolution of these clusters through time. The proposed graphical representation allows for the application of well known ... More
On the structure of open equivariant topological conformal field theoriesDec 10 2015We give a classification of open equivariant topological conformal field theories in terms of Calabi-Yau $A_\infty$-categories endowed with a group action.
Bounds on $g_5^Z$ from Precision LEP MeasurementsJun 16 1994Oct 28 1994The parity violating but CP conserving anomalous three-gauge-boson coupling $g_5^Z$ induces a universal contribution to the left-handed coupling of the $Z$ boson to fermions. We find that the LEP measurements of the partial $Z$ widths and lepton forward-backward ... More
$K_L \ra μ^\pm e^\mp ν\overlineν$ as background to $K_L \ra μ^\pm e^\mp$Feb 25 1993We consider the process $K_L \ra \mu^\pm e^\mp \nu \overline{\nu}$ at next to leading order in chiral perturbation theory. This process occurs in the standard model at second order in the weak interaction and constitutes a potential background in searches ... More
Quark-Lepton Unification and Rare Meson DecaysSep 01 1994We study meson decays mediated by the heavy gauge bosons of the Pati-Salam model of quark-lepton unification. We consider the scenarios in which the tau lepton is associated with the third, second, and first generation of quarks. The most sensitive probes, ... More
Spin correlations and new physics in $τ$-lepton decays at the LHCMay 08 2015Jul 09 2015We use spin correlations to constrain anomalous $\tau$-lepton couplings at the LHC including its anomalous magnetic moment, electric dipole moment and weak dipole moments. Single spin correlations are ideal to probe interference terms between the SM and ... More
Higgs production constraints on anomalous fermion couplingsOct 31 2014May 08 2015Certain anomalous fermion-gauge boson couplings, such as the flavor diagonal anomalous color magnetic (CMDM) and color electric (CEDM) dipole moments of quarks are not fully gauge invariant under the SM. Restoring gauge invariance with an elementary Higgs ... More
Ohmic Dissipation in Mini-NeptunesSep 06 2017In the presence of a magnetic field and weakly ionizing winds, ohmic dissipation is expected to take place in the envelopes of Jovian and lower-mass planets alike. While the process has been investigated on the former, there have been no studies done ... More
Controlling Non-Markovian Dynamics Using a Light-based Structured EnvironmentSep 04 2018We present the experimental control of Non-Markovian dynamics of open quantum systems simulated with photonic entities. The polarization of light is used as the system, whereas the surrounding environment is represented by light's spatial structure. The ... More
Experimental verification of a quantumness criterion for single systems based on a Bell-like inequalityAug 11 2016Sep 28 2016In this letter, we propose and experimentally test a quantumness criterion for single systems. The criterion is based on the violation of an already reported classical inequality. This inequality is expressed in terms of joint probabilities that we identify ... More
Spatial interference of light: transverse coherence and the Alford and Gold effectOct 15 2015Feb 04 2016We study the interference between two parallel-propagating Gaussian beams, originated from the same source, as their transverse separation is tuned. The interference pattern as a function of such separation lead us to determine the spatial coherence length ... More
The Impact of |Delta I|=5/2 Transitions in K-> pi pi DecaysJun 21 2000Jul 31 2000We consider the impact of isospin violation on the analysis of K-> pi pi decays. We scrutinize, in particular, the phenomenological role played by the additional weak amplitude, of |Delta I|=5/2 in character, incurred by the presence of isospin violation. ... More
|Delta I|=3/2 Decays of the Omega^- in Chiral Perturbation TheoryOct 01 1998We study the decays Omega^- -> Cascade+pion using heavy-baryon chiral perturbation theory to quantify the |Delta I|=1/2 rule in these decay modes. The ratio of |Delta I|=3/2 to |Delta I|=1/2 amplitudes is somewhat larger in these decays than it is in ... More
Signals For Parity Violation in the Electroweak Symmetry Breaking SectorAug 09 1993Feb 03 1994We consider the possibility of observing a parity violating but $CP$ conserving interaction in the symmetry breaking sector of the electroweak theory. We find that the best probe for such an interaction is a forward-backward asymmetry in $W^+W^-$ production ... More
Relations between ex falso, tertium non datur, and double negation eliminationApr 01 2013We show which implicational relations hold between the three principles ex falso sequitur quodlibet, tertium non datur, and double negation elimination, on the basis of minimal logic.
Probing lepton gluonic couplings at the LHCFeb 08 2012May 28 2012In an effective Lagrangian description of physics beyond the standard model, gluonic couplings of leptons that respect the symmetries of the standard model occur in operators of dimension eight. Normally the effect of such operators is much suppressed ... More
Two Higgs doublet models augmented by a scalar color octetJun 03 2016Sep 13 2016The LHC is now studying in detail the couplings of the Higgs boson in order to determine if there is new physics. Many recent studies have examined the available fits to Higgs couplings from the perspective of constraining two Higgs doublet models (2HDM). ... More
Hochschild homology and cohomology for involutive $A_\infty$-algebrasJan 03 2016We present a study of the homological algebra of bimodules over $A_\infty$-algebras endowed with an involution. Furthermore we introduce a derived description of Hochschild homology and cohomology for involutive $A_\infty$-algebras.
T-odd correlations from CP violating anomalous top-quark couplings revisitedJul 08 2008May 08 2009We revisit the effect of CP violating anomalous top-quark couplings in $t\bar{t}$ production and decay. We consider $t\bar{t}$ production through gluon fusion (and light $q{\bar q}$ annihilation) followed by top-quark decay into $bW$ or $b\ell\nu$. We ... More
The role of $D^{\star\star}$ in $B^-\to D_s^+ K^- π^-$Nov 07 2006Feb 09 2007The BaBar collaboration has recently reported the observation of the decay mode $B^-\to D_s^+ K^- \pi^-$. We investigate the role played by the $D^{\star\star}$ resonances in this decay mode using HQET. Although these resonances cannot appear as physical ... More
Bounds on Anomalous Gauge Boson Couplings From Partial Z Widths at LEPOct 25 1994We place bounds on anomalous gauge boson couplings from LEP data with particular emphasis on those couplings which do not contribute to $Z$ decays at tree level. We use an effective field theory formalism to compute the one-loop corrections to the $Z\rightarrow ... More
CP Violation in Hyperon Nonleptonic Decays within the Standard ModelNov 12 2002Jan 16 2003We calculate the CP-violating asymmetries A(Lambda_-^0) and A(Xi_-^-) in nonleptonic hyperon decay within the Standard Model using the framework of heavy-baryon chiral perturbation theory (chiPT). We identify those terms that correspond to previous calculations ... More
Rare and Radiative Kaon DecaysMar 04 1993We review the status of theory and experiment of very rare and forbidden kaon decays. We then review the radiative non-leptonic decays, and the associated Dalitz pair modes. We pay particular attention to the study of long distance physics in radiative ... More
T-odd correlations from top-quark CEDM in lepton plus jets top-pair eventsNov 04 2015Mar 18 2016There exist several recent studies of the top-quark CEDM in the context of searching for CP violating signals in top-quark pair production at the LHC. Most of these studies constrain the CEDM either from deviations in the top-pair cross section from its ... More
Constraining $τ$-lepton dipole moments and gluon couplings at the LHCMay 29 2013May 08 2015We study the constraints that can be placed on anomalous $\tau$-lepton couplings at the LHC. We use an effective Lagrangian description for physics beyond the standard model which contains the $\tau$-lepton anomalous magnetic moment, electric dipole moment ... More
Gravitational Lensing Statistics by Galaxy Clusters with Smoothness Parameter Depending on zDec 12 2007Using the Eikonal approximation we study the effect of the smoothness parameter in the Dyer-Roeder equation. We calculate the optical depth for dark halos with NFW profile, for the abundance the Press-Schechter formalism is used. We focus our analysis ... More
Proceedings 18th International Workshop on Expressiveness in ConcurrencyAug 20 2011This volume contains the proceedings of the 18th International Workshop on Expressiveness in Concurrency (EXPRESS 2011), which took place on 5th September 2011 in Aachen, as a satellite workshop of CONCUR 2011. The EXPRESS workshop series aim at bringing ... More
Minimal metrics on 6-dimensional complex nilmanifoldsSep 13 2013Sep 22 2013Let (N,J) be a real 2n-dimensional nilpotent Lie group endowed with an invariant complex structure. A left-invariant Riemannian metric on N compatible with J is said to be minimal, if it minimizes the norm of the invariant part of the Ricci tensor among ... More
Top and bottom tensor couplings from a color octet scalarDec 02 2016Feb 15 2017We compute the one-loop contributions from a color octet scalar to the tensor anomalous couplings of top and bottom quarks to gluons, photons and W bosons. We use known constraints on the parameters of the model to compare the predicted size of these ... More
Vector-meson contributions do not explain the rate and spectrum in K_L -> pi0 gamma gammaJul 15 2002Aug 12 2002We analyze the recent NA48 data for the reaction K_L -> pi0 gamma gamma with and without the assumption of vector meson dominance (VMD). We find that the data is well described by a three-parameter expression inspired by O(p^6) chiral perturbation theory. ... More
CP Violation in Non-Leptonic Omega^- DecaysNov 17 1998We estimate the size of the CP-violating rate asymmetry for the decay Omega^- -> Cascade + pion. Within the standard model we find a value of 2 x 10^(-5), and it could be as much as ten times larger if new physics is responsible for CP violation. Even ... More
Probing Anomalous Gauge Boson Couplings at LEPNov 10 1994We bound anomalous gauge boson couplings using LEP data for the $Z\rightarrow {\overline f} f$ partial widths. We use an effective field theory formalism to compute the one-loop corrections resulting from non-standard model three and four gauge boson ... More
K_L -> pi0 gamma gamma and the bound on the CP-conserving K_L -> pi0 e+e-May 01 2001Aug 01 2001It has been known for many years that there is a CP-conserving component for the decay mode K_L -> pi0 e+e- and that its magnitude can be obtained from a measurement of the amplitudes in the K_L -> pi0 gamma gamma decay mode. We point out that the usual ... More
Additional Isospin-Breaking Effects in ε^\prime/εSep 01 1999Sep 13 1999In the analysis of \epsilon^\prime/\epsilon it has been traditional to consider the isospin-breaking effects arising from electroweak-penguin contributions and from \pi^0-\eta and \pi^0-\eta^\prime mixing, yet additional isospin-violating effects exist. ... More
Looking for CP Violation in W Production and DecayApr 03 1995We describe CP violating observables in resonant $W^\pm$ and $W^\pm$ plus one jet production at the Tevatron. We present simple examples of CP violating effective operators, consistent with the symmetries of the Standard Model, which would give rise to ... More
Top and bottom tensor couplings from a color octet scalarDec 02 2016We compute the one-loop contributions from a color octet scalar to the tensor anomalous couplings of top and bottom quarks to gluons, photons and W bosons. We use known constraints on the parameters of the model to compare the predicted size of these ... More
Color-octet scalar decays to a gluon and an electroweak gauge boson in the Manohar-Wise modelOct 08 2018Oct 15 2018We evaluate the one loop amplitudes giving rise to couplings between a scalar color octet, a gluon, and an electroweak gauge boson. These one loop amplitudes could give rise to new physics signals in $\gamma$ jet, $Z$ jet and $W$ jet production at the ... More
LHC constraints on color octet scalarsMar 12 2017Jul 25 2017We extract constraints on the parameter space of the MW model by comparing the cross-sections for dijet, top-pair, dijet-pair, $t\bar t t \bar t$ and $b\bar b b \bar b$ productions at the LHC with the strongest available experimental limits from ATLAS ... More
Constraints on anomalous color dipole operators from Higgs boson production at the LHCApr 25 2013Apr 30 2013Physics beyond the standard model (SM) can be parameterized with an effective Lagrangian that respects the symmetries of the standard model and contains many operators of dimension six. We consider the subset of these operators that is responsible for ... More
Predicting Knot and Catenane Type of Products of Site-specific Recombination on Twist Knot SubstratesJul 15 2010Jun 22 2011Site-specific recombination on supercoiled circular DNA molecules can yield a variety of knots and catenanes. Twist knots are some of the most common conformations of these products and they can act as substrates for further rounds of site-specific recombination. ... More
Validity of two Higgs doublet models with a scalar color octet up to a high energy scaleMar 09 2017Mar 22 2017We have recently studied theoretical constraints on the parameters of a 2HDM augmented with a color-octet scalar. In this paper we consider the consequences of requiring the model to remain valid up to very high energy scales, such as the GUT scale. The ... More
Open heavy flavour and quarkonium production as a function of the multiplicity in pp and p-Pb collisions with ALICE at the LHCMar 29 2017Mar 30 2017Due to the large masses of beauty and charm quarks, their production cross sections can be computed in the framework of perturbative Quantum Chromodynamics. The correlation of quarkonium and open heavy-flavour hadron yields with charged particles produced ... More
Explicit equations from orbit reduction: one and two stagesJun 11 2018May 04 2019It is known that orbit reduction can be performed in one or two stages and it has been proven that the two processes are symplectically equivalent. In the context of orbit reduction by one stage we shall write an expression for the reduced two-form in ... More
Spherically Symmetric Non Linear StructuresMar 24 1996Aug 27 1996We present an analytical method to extract observational predictions about non linear evolution of perturbations in a Tolman Universe. We assume no a priori profile for them. We solve perturbatively a Hamilton - Jacobi equation for a timelike geodesic ... More
On Degenerations of Lie SuperalgebrasFeb 23 2018We give necessary conditions for the existence of degenerations between two complex Lie superalgebras of dimension $(m,n)$. As an application, we study the variety $\mathcal{LS}^{(2,2)}$ of complex Lie superalgebras of dimension $(2,2)$. First we give ... More
Equations derived from orbit reduction: one and two stagesJun 11 2018It is known that orbit reduction can be performed in one or two stages and it has been proven that the two processes are symplectically equivalent. In the context of orbit reduction by one stage we shall write an expression for the reduced two-form in ... More
On subgroups of finite index in branch groupsJan 28 2013Aug 28 2013We give a structural description of the normal subgroups of subgroups of finite index in branch groups in terms of rigid stabilizers. This gives further insight into the structure lattices of branch groups introduced by the second author. We derive a ... More
$A^b_{FB}$ and $R_b$ at LEP and New Right-Handed Gauge BosonsApr 23 2003We explore models with additional right-handed gauge bosons that couple predominantly to the third generation in the context of $b\bar{b}$ production at LEP. In particular we investigate potential new contributions to $\delta g_{Rb}$ that are needed if ... More
The decays $K \to ππν\overlineν$ within the standard modelDec 23 1995Oct 15 1996We study the reactions $K \rightarrow \pi \pi \nu \overline{\nu}$ within the minimal standard model. We use isospin symmetry to relate the matrix elements to the form factors measured in $K_{\ell 4}$. We argue that these modes are short distance dominated ... More
Lepton universality violation and right-handed currents in $b \to c τ ν$Nov 27 2017May 01 2018We consider the recent LHCb result for $B_c\to J/\psi \tau \nu$ in conjunction with the existing anomalies in $R(D)$ and $R(D^\star)$ within the framework of a right-handed current with enhanced couplings to the third generation. The model predicts a ... More
Arithmetical structures on graphs with connectivity oneJun 12 2016Jun 12 2017Given a graph $G$, an arithmetical structure on $G$ is a pair of positive integer vectors $({\bf d},{\bf r})$ such that $\mathrm{gcd}({\bf r}_v\, | \,v\in V(G))=1$ and \[ (\mathrm{diag}({\bf d})-A){\bf r}=0, \] where $A$ is the adjacency matrix of $G$. ... More
Ansatz for small FCNC with a non-universal $Z^\prime$Jul 23 2009Aug 18 2009It is well known that a non-universal $Z^\prime$ induces tree-level FCNC which are severely constrained by experiment, most notably meson mixing. We point out that there is a class of models, with a down-quark mass matrix of the Georgi-Jarlskog form, ... More