Neutral Pairs Research Articles

Laser-assisted CP-odd and CP-even Higgs bosons production in THDM

In this paper, we have theoretically studied the neutral Higgs pair production in Two Higgs Doublet Model (THDM) in the presence of a circularly polarized laser field. The laser-assisted differential partial cross section is derived in the centre of mass frame at the leading order including Z diagram. The total cross section is computed numerically by integrating the differential cross section over the solid angle . Two benchmark points are discussed for the THDM parameters. In the first step, we have analysed the total cross section of by considering H 0 as the standard model (SM)-like Higgs boson. Then, the process is studied by taking h 0 as the Higgs boson of the SM. For both benchmark points, the laser-assisted total cross section of the studied processes depends on the produced neutral Higgs masses, the centre of mass energy and the laser field parameters. In addition, the maximum cross section occurs at high centre of mass energy for the process as compared to that of .

The Role of Working Memory in Age-Related Emotional Memory Bias

Aging is accompanied by deterioration in both working memory (WM) and long-term memory (LTM), yet whether these changes are related is not understood. Sleep plays a role in the formation of LTM in young adults, but the findings in older adults are not as clear. The types of memories we store also shift with age as young adults preserve a higher proportion of negative experiences when compared to older adults. The reason for this age-related change in emotional memory bias is also not clear; however, some studies have suggested that WM changes across aging may be an important factor. In the current study, we examined performance in WM and emotional LTM in younger and older adults. We added a daytime nap in half the subjects to examine a possible role of sleep on emotional LTM. In the morning, 93 younger (18–39) and 121 older (60–85) adults completed a WM task. Subjects also encoded neutral or negative word pairs and provided valence and arousal ratings for each pair. After half the subjects took a daytime nap, LTM was examined, and valence and arousal ratings were reassessed. Results indicate that older adults showed worse recognition for negative word pairs compared with neutral, as well as decreased negative valence ratings in the afternoon. This decrease in emotional reactivity was correlated with better LTM performance. In contrast, younger adults performed better on the negative compared to neutral word pairs, with no change in emotional reactivity and no association between emotional reactivity and LTM. In addition, WM was positively related to LTM in younger, but not in older adults. Lastly, no differences were shown across sleep, regardless of age. Our findings suggest that the emotional memory bias may be associated with the emotional saliency of the information in older adults, and with WM capacity in younger adults.

Driving force and pathway in polyelectrolyte complex coacervation

There is notable discrepancy between experiments and coarse-grained model studies regarding the thermodynamic driving force in polyelectrolyte complex coacervation: experiments find the free energy change to be dominated by entropy, while simulations using coarse-grained models with implicit solvent usually report a large, even dominant energetic contribution in systems with weak to intermediate electrostatic strength. Here, using coarse-grained, implicit-solvent molecular dynamics simulation combined with thermodynamic analysis, we study the potential of mean force (PMF) in the two key stages on the coacervation pathway for symmetric polyelectrolyte mixtures: polycation-polyanion complexation and polyion pair-pair condensation. We show that the temperature dependence in the dielectric constant of water gives rise to a substantial entropic contribution in the electrostatic interaction. By accounting for this electrostatic entropy, which is due to solvent reorganization, we find that under common conditions (monovalent ions, room temperature) for aqueous systems, both stages are strongly entropy-driven with negligible or even unfavorable energetic contributions, consistent with experimental results. Furthermore, for weak to intermediate electrostatic strengths, this electrostatic entropy, rather than the counterion-release entropy, is the primary entropy contribution. From the calculated PMF, we find that the supernatant phase consists predominantly of polyion pairs with vanishingly small concentration of bare polyelectrolytes, and we provide an estimate of the spinodal of the supernatant phase. Finally, we show that prior to contact, two neutral polyion pairs weakly attract each other by mutually induced polarization, providing the initial driving force for the fusion of the pairs.

Effects of substituent and excess electron attachment on proton transfer between the radiosensitizer base pairs in aqueous solution

We investigate the proton transfer reaction of radiosensitizing drugs 5-substituted thymine-adenine (5XT-A, X = Br, OCN) in water solutions through the density functional theory (DFT) computations. The relaxed three-dimension potential energy surfaces (PESs) along the two-hydrogen bond of 5XT-A are constructed to reveal the possible proton transfer pathways. The calculations show that the single proton transfer of 5XT-A undergoes a lower energy barrier than that of normal base pair (5OCNT-A < 5BrT-A < T-A). With considering the excess electron attachment, the anion base pair (T-A)- possesses higher energy barrier associated to the proton transfer process. However, the (5XT-A, X = Br, OCN)- anions could dissociate into T•-A radical, which can promote the intermolecular proton transfer reaction between base pairs. It is found that both the neutral and anionic 5-subsituted base pairs can contribute to DNA mutation through the easier proton transfer reaction, which is qualitatively demonstrated by the substituent-induced hydrogen bond enhancement. Our results are helpful to understand the mechanism of enhanced DNA damage in radiotherapy, and are prospective for the design of radiosensitizing drugs without the biotoxicity.

A-288 Valenced Attention Shifting Deficits Evident via Eye-tracking and not Reaction Time Measures in a Psychiatric Sample

Abstract Objective: Inflexible attention shifting from dysphoric information is a key component of contemporary depression risk models. Yet, the literature is mixed concerning such deficits in depressed samples, perhaps partly due to construct-irrelevant variance (e.g., motor speed) that saturates some behavioral attention shifting measures. This study evaluates the clinical validity of an eye-tracking-based measure of motivated attention shifting in response to neutral and valenced stimuli. Method: Hungarian adults with depression histories (N=198; Mage=26.83, 45% female; n=28 depressed) completed psychiatric interviews (SCID), depression measures (BDI-II, PANAS-X), and a visual attention shifting task via E-prime 3.0 and Tobii x2-60 eye-tracking system. Participants viewed 72 same-actor face pairs (angry-neutral, sad-neutral, happy-neutral, neutral-neutral) drawn from the KDEF database; attention shifting indices (outcomes of interest) reflected visual attention shifting speed away from a sad- or happy-valenced face towards a neutral face (disengagement), in reverse order (engagement), and across neutral face pairs (valence-free shifting) in response to a visual prompt (i.e., a shape framing the target face). Parallel behavioral indices reflect reaction times to said visual prompts. Depression status, severity, and affects served as the validators. Results: Independent of demographics, valence-free shifting, and valid task trial frequency, current depression (βDep=.29, p=.016), low trait positive affect (βPANAS-X,PA=-.14, p=.02), and depression severity at a trend level (βBDI-II=.06, p=.059) predicted slow sad-face disengagement; no other effect reached significance. Conclusion: Results suggest that shifting visual attention away from sad, but not positively-valenced information may be linked to depressive states among formerly depressed persons and provide some evidence for the eye-tracking-based task’s incremental validity to behavioral parallels.

Quantum chemical calculations of formation enthalpies of cations and anions of ionic liquids

The development of advanced ionic-liquid-based applications requires accurate thermochemical data for both ionic liquids and their constituent ions. Herein, the formation enthalpies of alkylimidazolium cations ([CnMIm+], n = 2, 4, 6, 8, 10) and various anions (trifluoromethanesulfonate ([TfO−]), ethyl sulfate ([ES−]), dicyanamide ([DCA−]), and bis(trifluoromethane)sulfonylimide ([NTf2−])) in the ideal gas state were obtained by quantum chemical calculations using density functional theory (DFT: B3LYP, B98, M06, M06-2X) and composite (G4) thermochemical models in the framework of the isodesmic reaction approach. The enthalpies of heterolytic dissociation of neutral ion pairs (NIPs) for the [CnMIm+][X−] series (n = 2, 4, 6, 8, 10; X− = [TfO−], [ES−], [NTf2−], [DCA−], [BF4−], [PF6−], [Cl−], [Br−], [I−]) were derived using the obtained data and literature formation enthalpies (ΔfH°) of NIPs. Analysis of the thermochemical property trends revealed that the formation enthalpies of [CnMIm+] decrease linearly as the alkyl chain length increases. In addition, the use of the isodesmic reaction approach improved the reliability of the computed data. Furthermore, owing to its internal self-consistency, the G4 method was found to be the most appropriate for describing the thermodynamic quantities of the cations and anions of ionic liquids.

Pair production of neutral Higgs particles in the B-LSSM

Higgs pair production provides a unique handle for measuring the strength of Higgs self interaction and constraining the shape of the Higgs potential. Including radiative corrections to the trilinear couplings of CP-even Higgs, we investigate the cross section of the lightest neutral Higgs pair production in gluon fusion at the Large Hadron Collider in the supersymmetric extensions of the standard model. Numerical results indicate that the correction to the cross section is about 11% in the B-LSSM, while is only about 4% in the MSSM. Considering the constraints of the experimental data of the lightest Higgs, we find that the gauge couplings of U(1) B–L and the ratio of the nonzero vacuum expectation values of two singlets also affect strongly the theoretical evaluations on the production cross section in the B-LSSM.

π-Pimer, π-Dimer, π-Trimer, and 1D π-Stacks in a Series of Benzene Triimide Radical Anions: Substituent-Modulated π Interactions and Physical Properties in Crystalline State

π-Pimer, π-Dimer, π-Trimer, and 1D π-Stacks in a Series of Benzene Triimide Radical Anions: Substituent-Modulated π Interactions and Physical Properties in Crystalline State

Excitonic fractional quantum Hall hierarchy in moiré heterostructures

We consider fractional quantum Hall states in systems where two flat Chern number $C=\ifmmode\pm\else\textpm\fi{}1$ bands are labeled by an approximately conserved valley index and interchanged by time reversal symmetry. At filling factor $\ensuremath{\nu}=1$ this setting admits an unusual hierarchy of correlated phases of excitons, neutral particle-hole pair excitations of a fully valley-polarized orbital ferromagnet parent state where all electrons occupy a single valley. Excitons experience an effective magnetic field due to the Chern numbers of the underlying bands. This obstructs their condensation in favor of a variety of crystalline orders and gapped and gapless liquid states. All these have the same quantized charge Hall response and are electrically incompressible, but differ in their edge structure, orbital magnetization, and hence valley and thermal responses. We explore the relevance of this scenario for moir\'e heterostructures of bilayer graphene on a hexagonal boron nitride substrate.

Photoproduction of pion pairs at high energy and small angles

We explore the photoproduction mechanisms for charged and neutral pion pairs off a heavy nucleus at threshold. We calculate the production of charged pairs in the Coulomb field of the nucleus in the Born approximation using explicit expressions for the differential cross sections and their connection with the total cross section $\ensuremath{\sigma}(\ensuremath{\gamma}\ensuremath{\gamma}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})$. The production of $\ensuremath{\sigma}$ mesons at threshold and their subsequent decay into pions is an important mechanism and is investigated quantitatively in a framework that can be used for both charged and neutral pions. $\ensuremath{\sigma}$ mesons can be produced via electromagnetic (photon exchange) or strong ($\ensuremath{\omega}$ exchange) interactions. For neutral pions, another production mechanism consists of the two-step process where charged pions are produced first and then charge exchange into two neutral pions. Differential and total cross sections are computed for each production mechanism.

Parameter dependence and analysis of the 2HDM neutral Higgs boson pair production and decay at future lepton colliders

In this work, we present a study of the neutral Higgs bosons in the two Higgs doublet model (2HDM) in terms of their production processes and decay channels as a function of the model parameters. The analysis is performed for all four types of the 2HDM and the most promising processes and decay channels are identified for each type of the model. Several Higgs boson mass scenarios below and above the threshold of decay to gauge boson pair are introduced and the corresponding categories of final states are analyzed. The event analysis including collider beam spectrum and detector simulation shows that future lepton colliders have the potential to explore regions in the 2HDM parameter space, which have not yet been excluded by LHC, in a few weeks of operation. Final results are presented in terms of the signal distributions on top of the background and 95% CL exclusion and 5σ contours based on center of mass energy of s=500 GeV at the Compact Linear Collider (CLIC) or International Linear Collider (ILC).

Avoidance of mild threat observed in generalized anxiety disorder (GAD) using eye tracking

Attentional biases towards threat are assumed to be a causal factor in the development of anxiety disorders, including generalized anxiety disorder (GAD). However, findings have been inconsistent, and studies often examine single time-point bias during threat exposure, instead of across time. Attention to threat may shift throughout exposure (e.g., from initial engagement to avoidance), and research suggests that threat intensity and state anxiety influence attentional biases. No studies to our knowledge have examined biases across time and with varying threat intensity and state anxiety. Participants with GAD (n=38) and non-anxious controls (n=25) viewed emotional (high threat, mild threat, and positive) and neutral image pairs under calm and anxious mood states while their eye movements were tracked. Participants showed an initial orientation to emotional images, and, under the anxious mood induction, demonstrated a bias towards threatening images at first fixation and over time. Results suggest it may be normative to attend to threat cues over other stimuli while in an anxious state. Individuals with GAD uniquely showed a bias away from mild (but not high) threat images over time relative to controls. Implications for theories of attentional biases to threat and clinical implications for GAD and anxiety disorders broadly are discussed.

Theoretical and experimental comparison of rare earths extraction by [P6,6,6,1,4][Decanoate] bifunctional ionic liquid and D2EHPA acidic extractant

The extraction behavior of two lanthanides (La3+ and Y3+) in the nitric acid solution was studied using a bifunctional ionic liquid, namely Trihexyl-tetradecyl-phosphonium Decanoate ([P6,6,6,1,4] [Decanoate]). On comparative study on D2EHPA as a molecular extractant, the ionic liquid revealed remarkably higher extraction capacity of the total are earth elements. The ionic liquid had a separation factor for La/Y smaller than that of the molecular extractant. A high yttrium extraction with an efficiency of > 99% was observed for both extractants, even in low concentrations. The highest efficiency of D2EHPA (20%) equaled 75.04% in the extraction of lanthanum, while this magnitude was > 99% for lanthanum extraction by the ionic liquid. In this study, the Density Functional Theory (DFT) connected to Born Haber Thermodynamics was used along with the solvent effect, imported by the Conductor-like Screening Model (COSMO), for confirming and interpreting the selectivity results, which were observed in the laboratory during the extraction of lanthanum and yttrium. Calculation of the difference in the energy levels of the molecular orbitals of [P6,6,6,1,4] [Decanoate] in the extraction of the neutral complexes of [La.(NO3)3. (H2O)3] ΔEorbital = 0.16 eV) and [Y.(NO3)3. (H2O)2] (ΔEorbital = 0.17 eV) with the neutral or ion pair exchange has shown that this ionic liquid was more efficient than D2EHPA with a cation exchange mechanism in the extraction of the ionic complexes of these elements.

Dark exciton anti-funneling in atomically thin semiconductors

Transport of charge carriers is at the heart of current nanoelectronics. In conventional materials, electronic transport can be controlled by applying electric fields. Atomically thin semiconductors, however, are governed by excitons, which are neutral electron-hole pairs and as such cannot be controlled by electrical fields. Recently, strain engineering has been introduced to manipulate exciton propagation. Strain-induced energy gradients give rise to exciton funneling up to a micrometer range. Here, we combine spatiotemporal photoluminescence measurements with microscopic theory to track the way of excitons in time, space and energy. We find that excitons surprisingly move away from high-strain regions. This anti-funneling behavior can be ascribed to dark excitons which possess an opposite strain-induced energy variation compared to bright excitons. Our findings open new possibilities to control transport in exciton-dominated materials. Overall, our work represents a major advance in understanding exciton transport that is crucial for technological applications of atomically thin materials.

Vacuum instability due to the creation of neutral fermion with anomalous magnetic moment by magnetic-field inhomogeneities

We study neutral fermions pair creation with anomalous magnetic moment from the vacuum by time-independent magnetic-field inhomogeneity as an external background. We show that the problem is technically reduced to the problem of charged-particle creation by an electric step, for which the nonperturbative formulation of strong-field QED is used. We consider a magnetic step given by an analytic function and whose inhomogeneity may vary from a “gradual” to a “sharp” field configuration. We obtain corresponding exact solutions of the Dirac-Pauli equation with this field and calculate pertinent quantities characterizing vacuum instability, such as the differential mean number and flux density of pairs created from the vacuum, vacuum fluxes of energy and magnetic moment. We show that the vacuum flux in one direction is formed from fluxes of particles and antiparticles of equal intensity and with the same magnetic moments parallel to the external field. Backreaction to the vacuum fluxes leads to a smoothing of the magnetic-field inhomogeneity. We also estimate critical magnetic field intensities, near which the phenomenon could be observed.

The Composition of Saturated Vapor over 1-Butyl-3-methylimidazolium Tetrafluoroborate Ionic Liquid: A Multi-Technique Study of the Vaporization Process.

A multi-technique approach based on Knudsen effusion mass spectrometry, gas phase chromatography, mass spectrometry, NMR and IR spectroscopy, thermal analysis, and quantum-chemical calculations was used to study the evaporation of 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4). The saturated vapor over BMImBF4 was shown to have a complex composition which consisted of the neutral ion pairs (NIPs) [BMIm+][BF4−], imidazole-2-ylidene C8N2H14BF3, 1-methylimidazole C4N2H6, 1-butene C4H8, hydrogen fluoride HF, and boron trifluoride BF3. The vapor composition strongly depends on the evaporation conditions, shifting from congruent evaporation in the form of NIP under Langmuir conditions (open surface) to primary evaporation in the form of decomposition products under equilibrium conditions (Knudsen cell). Decomposition into imidazole-2-ylidene and HF is preferred. The vapor composition of BMImBF4 is temperature-depended as well: the fraction ratio of [BMIm+][BF4−] NIPs to decomposition products decreased by about a factor of three in the temperature range from 450 K to 510 K.

Evidence for the formation of two types of oxygen interstitials in neutron-irradiated \u03b1-Al2O3 single crystals

Due to unique optical/mechanical properties and significant resistance to harsh radiation environments, corundum (α-Al2O3) is considered as a promising candidate material for windows and diagnostics in forthcoming fusion reactors. However, its properties are affected by radiation-induced (predominantly, by fast neutrons) structural defects. In this paper, we analyze thermal stability and recombination kinetics of primary Frenkel defects in anion sublattice − the F-type electronic centers and complementary oxygen interstitials in fast-neutron-irradiated corundum single crystals. Combining precisely measured thermal annealing kinetics for four types of primary radiation defects (neutral and charged Frenkel pairs) and the advanced model of chemical reactions, we have demonstrated for the first time a co-existence of the two types of interstitial defects – neutral O atoms and negatively charged O- ions (with attributed optical absorption bands peaked at energies of 6.5 eV and 5.6 eV, respectively). From detailed analysis of interrelated kinetics of four oxygen-related defects, we extracted their diffusion parameters (interstitials serve as mobile recombination partners) required for the future prediction of secondary defect-induced reactions and, eventually, material radiation tolerance.

Sensitivity to triple Higgs couplings via di-Higgs production in the 2HDM at e^+e^- colliders

An important task at future colliders is the investigation of the Higgs-boson sector. Here the measurement of the triple Higgs coupling(s) plays a special role. Based on previous analyses, within the framework of Two Higgs Doublet Models (2HDM) type I and II, we define and analyze several two-dimensional benchmark planes, that are over large parts in agreement with all theoretical and experimental constraints. For these planes we evaluate di-Higgs production cross sections at future high-energy e^+e^- colliders, such as ILC or CLIC. We consider two different channels for the neutral di-Higgs pairs h_i h_j=hh,hH,HH,AA: e^+e^- rightarrow h_i h_j Z and e^+e^- rightarrow h_i h_j nu {{bar{nu }}}. In both channels the various triple Higgs-boson couplings contribute substantially. We find regions with a strong enhancement of the production channel of two SM-like light Higgs bosons and/or with very large production cross sections involving one light and one heavy or two heavy 2HDM Higgs bosons, offering interesting prospects for the ILC or CLIC. The mechanisms leading to these enhanced production cross sections are analyzed in detail. We propose the use of cross section distributions with the invariant mass of the two final Higgs bosons where the contributions from intermediate resonant and non-resonant BSM Higgs bosons play a crucial role. We outline which process at which center-of-mass energy would be best suited to probe the corresponding triple Higgs-boson couplings.

Laser-assisted neutral Higgs-boson pair production in Inert Higgs Doublet Model (IHDM)

In the framework of the Inert Higgs Doublet model (IHDM), we have investigated, in the centre of mass frame, the neutral Higgs-boson pair production in the presence of an intense and circularly polarized laser field via e+e− annihilation (e+e−→H0A0) at the lowest order. By using the scattering matrix method, we have derived the analytical expression of the differential cross section. The latter is numerically integrated over the solid angle to obtain the total cross section. Then, we have shown how this total cross section depends on the outgoing particles mass for different number of exchanged photons. Next, we have illustrated its variation as a function of the centre of mass energy for different neutral Higgs-boson masses. Finally, we have indicated how it changes as a function of the laser field amplitudes for both different number of exchanged photons and different neutral Higgs-bosons masses.

Acidic Cannabinoid Decarboxylation.

Introduction:Cannabis is a valuable plant, cultivated by humans for millennia. However, it has only been in the past several decades that biologists have begun to clarify the interesting Cannabis biosynthesis details, especially the production of its fascinating natural products termed acidic cannabinoids. Discussion: Acidic cannabinoids can experience a common organic chemistry reaction known as decarboxylation, transforming them into structural analogues referred to as neutral cannabinoids with far different pharmacology. This review addresses acidic and neutral cannabinoid structural pairs, when and where acidic cannabinoid decarboxylation occurs, the kinetics and mechanism of the decarboxylation reaction as well as possible future directions for this topic. Conclusions: Acidic cannabinoid decarboxylation is a unique transformation that has been increasingly investigated over the past several decades. Understanding how acidic cannabinoid decarboxylation occurs naturally as well as how it can be promoted or prevented during harvesting or storage is important for the various stakeholders in Cannabis cultivation.