Triplet Model Research Articles

Search for heavy resonances decaying to ZZ or ZW and axion-like particles mediating nonresonant ZZ or ZH production at sqrt{s} = 13 TeV

A search has been performed for heavy resonances decaying to ZZ or ZW and for axion-like particles (ALPs) mediating nonresonant ZZ or ZH production, in final states with two charged leptons (ℓ = e, μ) produced by the decay of a Z boson, and two quarks produced by the decay of a Z, W, or Higgs boson H. The analysis is sensitive to resonances with masses in the range 450 to 2000 GeV. Two categories are defined corresponding to the merged or resolved reconstruction of the hadronically decaying boson. The search is based on data collected during 2016–2018 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb−1. No significant excess is observed in the data above the standard model background expectation. Upper limits on the production cross section of heavy, narrow spin-2 and spin-1 resonances are derived as functions of the resonance mass, and exclusion limits on the production of bulk graviton particles and W′ bosons are calculated in the framework of the warped extra dimensions and heavy vector triplet models, respectively. In addition, upper limits on the ALP-mediated diboson production cross section and ALP couplings to standard model particles are obtained in the framework of linear and chiral effective field theories. These are the first limits on nonresonant ALP-mediated ZZ and ZH production obtained by the LHC experiments.

TCL: Tightly Coupled Learning Strategy for Weakly Supervised Hierarchical Place Recognition

Visual place recognition (VPR) is a key issue for robotics and autonomous systems. For the trade-off between time and performance, most of methods use the coarse-to-fine hierarchical architecture, which consists of retrieving top-N candidates using global features, and re-ranking top-N with local features. However, since the two types of features are usually processed independently, re-ranking may harm global retrieval, termed re-ranking confusion. Moreover, re-ranking is limited by global retrieval. In this paper, we propose a tightly coupled learning (TCL) strategy to train triplet models. Different from original triplet learning (OTL) strategy, it combines global and local descriptors for joint optimization. In addition, a bidirectional search dynamic time warping (BS-DTW) algorithm is also proposed to mine locally spatial information tailored to VPR in re-ranking. The experimental results on public benchmarks show that the models using TCL outperform the models using OTL, and TCL can be used as a general strategy to improve performance for weakly supervised ranking tasks. Further, our lightweight unified model is better than several state-of-the-art methods and has over an order of magnitude of computational efficiency to meet the real-time requirements of robots.

Dressed behavior of the quasiparticles lifetime in the unitary limit of two unconventional superconductors

We compare the quasiparticle lifetime behavior in the unitary limit of two unconventional superconductors dressed by nonmagnetic impurity scattering to differentiate an anomalous functional behavior in its shape when the disorder concentration is changed in a triplet paired model with respect to the well behave singlet model. For singlet paired superconductors, the functional shape of the lifetime due to elastic scattering around the nodal regions in the reduced elastic scattering space, does not change with the disorder concentration, but for a triplet model with a tiny gap, an anomalous drop in shape is observed only when small values of disordering are added. We use a 2D tight-binding parametrization to study the reduced phase space of the first Brillouin zone, where the low-energy scattering is restricted to the nodal/quasinodal regions for two irreducible representations of the crystal lattice. A new class of Wigner probabilistic distribution functions is discussed for triplet superconductors.

Компьютерное моделирование наноскопических фазово-неоднородных состояний и фазовых диаграмм ВТСП купратов и никелатов

More than 35 years of experience in the study of cuprate superconductors shows that the main characteristics of the phase diagram can only be obtained by taking into account mesoscopic static/dynamic phase inhomogeneity as a key property of these materials. Within a minimal model for the CuO2 planes with the on-site Hilbert space reduced to only three effective valence centers [CuO4]7-,6-,5- (nominally Cu1+,2+,3+) with different conventional spin and different orbital symmetry we propose a unified non-BCS model that allows one to describe the main features of the phase diagrams of doped cuprates within the framework of a simple effective field theory. Using Maxwell's construction, the global nature of the electronic phase separation in the CuO2 planes of HTSC cuprates is established, which makes it possible to understand and explain many fundamental features of the physics of the normal and superconducting state of cuprates, including the mechanism of formation of the HTSC and pseudogap phase. The features of phase-inhomogeneous states and their evolution with temperature and doping degree, including the special role of the impurity potential in cuprates/nickelates with nonisovalent substitution, are considered for particular examples of the charge triplet model in the framework of the classical Monte Carlo method.

Computer simulation of nanoscopic phase-inhomogeneous states and phase diagrams of HTSC cuprates and nickelates

More than 35 years of experience in the study of cuprate superconductors shows that the main characteristics of the phase diagram can only be obtained by taking into account mesoscopic static/dynamic phase inhomogeneity as a key property of these materials. Within a minimal model for the CuO2/NiO2 planes with the on-site Hilbert space reduced to only three effective valence centers [CuO4]7-,6-,5- (nominally Cu1+,2+,3+) with different conventional spin and different orbital symmetry we propose a unified non-BCS model that allows one to describe the main features of the phase diagrams of doped cuprates within the framework of a simple effective field theory. Using Maxwell's construction, the global nature of the electronic phase separation in the CuO2 planes of HTSC cuprates is established, which makes it possible to understand and explain many fundamental features of the physics of the normal and superconducting state of cuprates, including the mechanism of formation of the HTSC and pseudogap phase. The features of phase-inhomogeneous states and their evolution with temperature and doping degree, including the special role of the impurity potential in cuprates/nickelates with nonisovalent substitution, are considered for particular examples of the charge triplet model in the framework of the classical Monte Carlo method. Keywords: cuprates, nickelates, effective field theory, phase diagram, phase separation, Monte-Carlo.

A deformable CNN-based triplet model for fine-grained sketch-based image retrieval

With the popularity of electronic touch-screen and pressure sensing devices, fine-grained sketch based image retrieval (FG-SBIR) has become a research hotspot. In this paper, we stress the core problems of FG-SBIR: a. how to reduce the difference between the non-homogenous of heterogeneous media, and b. how to improve the distinguishability of sketch features. Specifically, a sketch generation model is first proposed to replace the conventional pre-processing of roughly extracting image edges, moreover, this model can alleviate the dilemma of sketch data scarcity. We then construct a novel FG-SBIR model which takes advantage of deformable convolutional neural network while taking into consideration of semantic attributes together. In addition, we build a fine-grained clothing sketch-image dataset, which has rich attribute annotations, for the first time. Extensive experiments exhibit that our proposed model achieves a better performance in improving the retrieval accuracy over the state-of-the-art baselines.

FIMP DM in the extended hyperchargeless Higgs triplet model

We perform an exclusive study on the feebly interacting massive particle dark matter candidate in an extended hyperchargeless ($Y=0$) Higgs triplet model. The additional ${Z}_{2}$ odd neutral fermion singlet plays the role of dark matter with support from two other vectorlike fermion doublets. The mixing between the neutral component of a doublet and singlet fermions controls the current relic density through the freeze-in mechanism, whereas the additional doublet fermion helps to get the neutrino mass and mixing angles. We obtain a broad region of the parameter spaces satisfying the current relic density and neutrino mass and mixing angles.

Probing extended scalar sectors with precision e+e\u2212\u2192 Zh and Higgs diphoton studies

We compute the one-loop corrections to σ(e+e−→ Zh) arising from representative extended Standard Model scalar sector scenarios. According to the new scalar SU(2)L representations, we consider the inert doublet, real and complex triplet, quintuplet, and septuplet models. With the sub-percent level precision expected for prospective future e+e− collider measurements of σ(e+e−→ Zh), studies of the Higgsstrahlung process will probe extended scalar sector particle spectrum and interactions in a manner complementary to direct searches at the Large Hadron Collider and possible future pp colliders. We also compare with the sensitivity of future Higgs diphoton decay rate measurements. We find that the σ(e+e−→ Zh) and Γ(h → γγ) complementarity is particularly pronounced for the complex triplet model.

The Mean Single Molecule Rate (mSMR) in the Analysis of Fluorescence Fluctuations: Measurements on DNA Mixtures of Defined Composition

We present a method for the evaluation of fluorescence fluctuations on the basis of Mandel’s Q parameter, using sampling time-dependent factorial cumulants. By relating the Q parameter to the sampling time, we obtain the mean single molecule rate (mSMR), an easy to interpret expression that provides both brightness and diffusion information. The model is suitable for the widely used confocal setups with single photon excitation and a single detection channel. We present a way to correct the mSMR for afterpulsing, dead time and background noise. To account for photokinetic effects at short sampling times, we expand the model by a simple on/off isomerization term, which is similar to the well-known triplet model. The functionality of the mSMR is shown using Monte Carlo simulations. The correction mechanisms and the experimental applicability of the model are then demonstrated by DNA measurements of defined composition. By systematically analyzing DNA mixtures, we can show that at large sampling times, the mSMR correctly describes the single molecule brightness rates and the diffusive properties of DNA molecules. At short sampling times, the photokinetic effects of isomerization are accurately described by the mSMR model. Since additionally the mSMR can easily be corrected for measurement artefacts such as detector dead time, afterpulsing and background noise, this is a valuable advantage over the standard method of fluorescence correlation spectroscopy.

Muon g−2 in a two-Higgs-doublet model with a type-II seesaw mechanism

We study the two-Higgs-doublet model with type-II seesaw mechanism. In view of constraints from the Higgs data, we consider the aligned two-Higgs-doublet scheme and its effects on muon anomalous magnetic dipole moment, $a_{\mu}$, including both one-loop and two-loop Barr-Zee type diagrams. Thanks to a sizable trilinear scalar coupling, the Barr-Zee type diagrams mediated by the Higgs triplet fields have a dominant effect on $a_{\mu}$. In particular, unlike the usual two-Higgs-doublet models that require exotic Higgs bosons light in mass, the masses of the corresponding particles in the model are of ${\cal O}(100)$~GeV. The doubly-charged Higgs boson presents a different decay pattern from the usual Higgs triplet model and thus calls for a new collider search strategy, such as multi-$\tau$ searches at the LHC.

Deep perceptual embeddings for unlabelled animal sound events.

Evaluating sound similarity is a fundamental building block in acoustic perception and computational analysis. Traditional data-driven analyses of perceptual similarity are based on heuristics or simplified linear models, and are thus limited. Deep learning embeddings, often using triplet networks, have been useful in many fields. However, such networks are usually trained using large class-labelled datasets. Such labels are not always feasible to acquire. We explore data-driven neural embeddings for sound event representation when class labels are absent, instead utilising proxies of perceptual similarity judgements. Ultimately, our target is to create a perceptual embedding space that reflects animals' perception of sound. We create deep perceptual embeddings for bird sounds using triplet models. In order to deal with the challenging nature of triplet loss training with the lack of class-labelled data, we utilise multidimensional scaling (MDS) pretraining, attention pooling, and a triplet mining scheme. We also evaluate the advantage of triplet learning compared to learning a neural embedding from a model trained on MDS alone. Using computational proxies of similarity judgements, we demonstrate the feasibility of the method to develop perceptual models for a wide range of data based on behavioural judgements, helping us understand how animals perceive sounds.

Discriminating the HTM and MLRSM models in collider studies via doubly charged Higgs boson pair production and the subsequent leptonic decays * *The research has been supported by the Polish National Science Center (NCN) under grant 2015/17/N/ST2/04067, COST (European Cooperation in Science and Technology) Action CA16201 PARTICLEFACE and the research activities co-financed by the funds granted under the Research Excellence

We present a case study for the doubly charged Higgs boson pair production in and pp colliders with their subsequent decays to four charged leptons. We consider the Higgs Triplet Model ( ), which is not restricted by the custodial symmetry, and the Minimal Left-Right Symmetric Model ( ). These models include scalar triplets with different complexities of scalar potentials and, because of experimental restrictions, completely different scales of non-standard triplet vacuum expectation values. In both models, a doubly charged Higgs boson can acquire a mass of hundreds of gigaelectronvolts, which can be probed at the HL-LHC, future , and hadron colliders. We take into account a comprehensive set of constraints on the parameters of both models coming from neutrino oscillations, LHC, , and low-energy lepton flavor violating data and assume the same mass of . Our finding is that the pair production in lepton and hadron colliders is comparable in both models, though more pronounced in the . We show that the decay branching ratios can be different within both models, leading to distinguishable four-lepton signals, and that the strongest are events yielded by the . Typically, we find that the signals are one order of magnitude larger those in the . For example, the signal for 1 TeV mass results in a clearly detectable significance of for the HL-LHC and for the FCC-hh. Finally, we provide quantitative predictions for the dilepton invariant mass distributions and lepton separations, which help to identify non-standard signals.

Electroweak phase transition in an inert complex triplet model

We study the dynamics of electroweak phase transition in a simple extension of the Standard Model where the Higgs sector is extended by adding an $SU(2)_L$-triplet with hypercharge Y=2. By making random scans over the parameters of the model, we show that there are regions consistent with constraints from collider experiments and the requirement for a strong first-order electroweak phase transition which is needed for electroweak baryogenesis. Further, we also study the power spectrum of the gravitational waves which can be generated due to the first-order phase transitions. Moreover, the detectability of these gravitational waves, via future space-based detectors, is discussed.

Prospect of the search for $${\mathrm {W}}^{\prime }$$ in vector boson fusion at the high-luminosity large hadron collider

A search for a new heavy charged gauge boson $${\mathrm {W}}^{\prime }$$ produced via a vector boson fusion process with two hard jets in pp collisions in the high-luminosity Large hadron collider (HL-LHC) environment is presented. The HL-LHC will increase the peak instantaneous luminosity to $$7.5 \times 10^{34}~{\mathrm {cm}}^{-2}~{\mathrm {s}}^{-1}$$ and the center of mass energy of 14 TeV to collect integrated luminosities up to 3 $${\mathrm {ab}}^{-1}$$ , which will significantly improve sensitivity for the observation of new heavy particles via rare processes. In this paper, to investigate the signal sensitivity for a $${\mathrm {W}}^{\prime }$$ we use the heavy vector triplet model, in the context of a simplified phenomenological approach, under Monte-Carlo simulations. The search targets events with one energetic electron and large missing transverse momentum, as well as two jets with a large separation in pseudorapidity. The expected upper limit for the mass of $${\mathrm {W}}^{\prime }$$ and exclusion limit contour on coupling parameters are presented at the 95% confidence level for an integrated luminosity of 3 $${\mathrm {ab}}^{-1}$$ .

Search for resonances decaying into a weak vector boson and a Higgs boson in the fully hadronic final state produced in proton−proton collisions at s=13 TeV with the ATLAS detector

A search for heavy resonances decaying into a $W$ or $Z$ boson and a Higgs boson produced in proton$-$proton collisions at the Large Hadron Collider at $\sqrt{s} = 13$ TeV is presented. The analysis utilizes the dominant $W \to q \bar{q}^\prime$ or $Z \to q \bar{q}$ and $H \to b \bar{b}$ decays with substructure techniques applied to large-radius jets. A sample corresponding to an integrated luminosity of 139 fb$^{-1}$ collected with the ATLAS detector is analyzed and no significant excess of data is observed over the background prediction. The results are interpreted in the context of the Heavy Vector Triplet model with spin-1 $W^\prime$ and $Z^\prime$ bosons. Upper limits on the cross section are set for resonances with mass between 1.5 and 5.0 TeV, ranging from 6.8 to 0.53 fb for $W^\prime \to WH$ and from 8.7 to 0.53 fb for $Z^\prime \to ZH$ at the 95 % confidence level.

Distinguishing inert Higgs doublet and inert triplet scenarios

In this article we consider a comparative study between Type-I 2HDM and Y=0, SU(2) triplet extensions having one Z_2-odd doublet and triplet that render the desired dark matter(DM). For the inert doublet model (IDM) either a neutral scalar or pseudoscalar can be the DM, whereas for inert triplet model (ITM) it is a CP-even scalar. The bounds from perturbativity and vacuum stability are studied for both the scenarios by calculating the two-loop beta functions. While the quartic couplings are restricted to 0.1-0.2 for a Planck scale perturbativity for IDM, these are much relaxed (0.8 ) for ITM. The RG-improved potentials by Coleman-Weinberg show the regions of stability, meta-stability and instability of the electroweak vacuum. The constraints coming from DM relic, the direct and indirect experiments like XENON1T, LUX and H.E.S.S., Fermi-LAT allow the DM mass gtrsim 700, ,1176 GeV for IDM, ITM respectively. Though mass-splitting among Z_2-odd particles in IDM is a possibility for ITM we have to rely on loop-corrections. The phenomenological signatures at the LHC show that the mono-lepton plus missing energy with prompt and displaced decays in the case of IDM and ITM can distinguish such scenarios at the LHC along with other complementary modes.

Interfacial behavior of cement stabilized rammed earth: Experimental and numerical study

Cement stabilised rammed earth (CSRE) is a modern earth construction technology witnessing renewed interest by researchers worldwide due to its improved strength and durability vis-a-vis un-stabilised rammed earth (URE). Rammed earth walls are predominantly subjected to compressive loading and occasionally to lateral loads. Strength and deformation ability of interface in rammed earth plays a vital role in case of in-plane lateral loads. The present study focuses on assessing the performance of interface layers in cement stabilized rammed earth elements. Triplet test is conducted on CSRE specimens under dry and saturated condition. Three types of bonding techniques are considered for the interface in CSRE triplets, namely, (i) formation of dents (ii) coating cement slurry across interfacial area (iii) combination of dents and slurry. The influence of stresses normal to the interface of CSRE triplet is also explored in this study. Further, a finite element simulation of the CSRE triplet test is performed. A finite element model of the CSRE triplet is developed by using ABAQUS software. Eight node brick elements are adopted to model the CSRE material and interface. Linear elastic material model is adopted for the CSRE material whereas a PPR-potential based cohesive model is adopted for the interface. Shear stress-displacement curve obtained from the finite element model and experiment are compared with each other and were found to be in reasonable agreement.

Nobel Prize Level Scientific Discoveries of a Heir of Zaporizhian Cossacks

In this work, three fundamental discoveries of the Ukraine-born Prof. George A. Gamow are presented from a single scientific and methodological point of view. Each of them is truly worth of the Nobel Prize – the most prestigious recognition of achievements of a scientist.
 We trace the emergence of G. Gamow as one of the most outstanding scientists of the twentieth century – encyclopaedist, theoretical physicist by heart, astrophysicist and biophysicist, talented and brilliant popularizer of science, whose works are readable in one go, as well as the author of unforgettable pranks and jokes.
 
 Gamow was a Fellow of the Danish Royal Academy of Sciences, the American Academy of Arts and Sciences, the International Astronomical Union, the American Physical Society, an honorary doctor of countless universities. Although his name is little known in Ukraine, the history of science would be incomplete without him.
 
 From an early age G. Gamow has shown a great interest in scientific research, using a microscope to look for erythrocytes and a telescope to observe the Halley comet. He graduated from the Faculty of Physics and Mathematics of Leningrad State University, where he followed classes of Professor O. Friedman, founder of the evolutionary cosmology. He has undergone training at the University of Goettingen, the center of theoretical physics at the time, worked for Nobel Prize winners Professors E. Rutherford and N. Bohr. At the age of 28, G. Gamow, by the recommendation of academician V. Vernadskyi, became the member of the Academy of Sciences of USSR, the youngest member in the entire history of its existence.
 Throughout his life, G. Gamow was interested in the fundamental scientific problems and made numerous world-class discoveries that are written by golden letters in the treasury of the human civilization. He has found explanation to the E. Rutherford’s experiments with alpha particles (tunnelling effect); introduced the empirical formula of Geiger – Nettoll, connecting the energy of alpha particles to the half-life of radioactive nuclei. G. Gamow is one of the pioneers of the liquid-drop model of a nucleus, and the application of nuclear physics to the evolution of stars. He proposed a fantastic hypothesis about the early universe, suggesting it being not only super dense but also very hot. He also built the Big Bang theory, which led to the existence of relic radiation (space microwave background) with the characteristic temperature of 5–7 degrees above the absolute zero, detected by methods of radio astronomy. He proposed a triplet model of the genetic code - the alphabet of life with three-letter words, experimentally proven by X-ray structural studies of DNA and empirically established rules of E. Chargaff. These discoveries have greatly contributed not only to the development of the modern science, but to the industrial and economic expansion of humanity.

Autonomous emergence of connectivity assemblies via spike triplet interactions.

Non-random connectivity can emerge without structured external input driven by activity-dependent mechanisms of synaptic plasticity based on precise spiking patterns. Here we analyze the emergence of global structures in recurrent networks based on a triplet model of spike timing dependent plasticity (STDP), which depends on the interactions of three precisely-timed spikes, and can describe plasticity experiments with varying spike frequency better than the classical pair-based STDP rule. We derive synaptic changes arising from correlations up to third-order and describe them as the sum of structural motifs, which determine how any spike in the network influences a given synaptic connection through possible connectivity paths. This motif expansion framework reveals novel structural motifs under the triplet STDP rule, which support the formation of bidirectional connections and ultimately the spontaneous emergence of global network structure in the form of self-connected groups of neurons, or assemblies. We propose that under triplet STDP assembly structure can emerge without the need for externally patterned inputs or assuming a symmetric pair-based STDP rule common in previous studies. The emergence of non-random network structure under triplet STDP occurs through internally-generated higher-order correlations, which are ubiquitous in natural stimuli and neuronal spiking activity, and important for coding. We further demonstrate how neuromodulatory mechanisms that modulate the shape of the triplet STDP rule or the synaptic transmission function differentially promote structural motifs underlying the emergence of assemblies, and quantify the differences using graph theoretic measures.

The Development of Research in the Field of Chemistry Education at the University of Novi Sad since the Breakup of the Socialist Federal Republic of Yugoslavia

The first PhD thesis in the field of Chemistry Education at the Faculty of Sciences, University of Novi Sad, was defended in 1992. This can be regarded as the symbolic dawn of Chemistry Education as a scientific discipline in this region. After the official breakup of the Socialist Federal Republic of Yugoslavia, research that had started in the 1980s, and which was focused on the development of tools for assessing the quality and flexibility of student knowledge, was continued through the 1990s. This research included the application of computers to chemistry teaching, as well as the development of appropriate chemistry learning programmes. In the following period, research focused on the analysis of chemical teaching programmes in the Republic of Serbia, with a special emphasis on the possibility of including eco-chemical content in curricula. Accordingly, potentially efficient models were suggested. The most recent research has been focused on the investigation of the effectiveness of instructional strategies based on a systemic approach and a triplet model of content representation, using combined measures of students’ performance and mental effort. In this regard, tools for the efficient assessment of knowledge (systemic synthesis questions, context-based questions) have been developed along with tools for the efficient assessment of students’ misconceptions (multi-tier tests). Furthermore, in order to make teaching more effective, procedures for assessing the cognitive complexity of chemical problems have recently been developed and subsequently validated both statistically and by applying Knowledge Space Theory.