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Tau τ - is the most massive lepton. Therefore, it has several decay channels. Unlike other leptons, tau can decay into hadronic and leptonic particles. In this article, we have studied the leptonic ( τ - → ν τ ℓ - ν ¯ ℓ ) and two-body hadronic ( τ - → ν τ h - ) decays of tau, where ℓ - represents the electron or muon, and h - refers to one of the mesons π - or K - , in the presence of a circularly polarized monochromatic laser field. Using the Dirac–Volkov formalism for fermions and that of Klein-Gordon for mesons, we have analytically calculated the expression for the total width of the laser-assisted tau decay at the lowest order. We have examined the variation of the total decay width, the multiphoton absorption and emission process, as well as the branching ratios and lifetime as a function of the parameters that characterize the laser field. The results show that the insertion of the laser field reduces the total decay width, and consequently extends the lifetime due to the quantum Zeno effect. More importantly, we found that the application of a laser field with an appropriate frequency and field strength alters the decay width by enhancing some decay modes and suppressing others. [ABSTRACT FROM AUTHOR]

The standard model Higgs boson has various decay modes, some of which have been measured in the CMS and ATLAS experiments, located at the Large Hadron Collider at CERN. This paper, calculates the decay of the standard model Higgs boson into D ∗ ± meson through the mechanism direct fragmentation. In this approach, the Higgs boson, first decays into c c ¯ and b b ¯ pairs, and then the heavy quarks fragment directly into D ∗ ± meson. The branching ratios of the SM Higgs boson into D ∗ ± meson have been calculated by considering NLO and NNLO corrections in the fragmentation functions of D ∗ ± . [ABSTRACT FROM AUTHOR]

We study the strong decays of the ϕ (2170) , along with its possible partner X (2436) , as two fully strange tetraquark states of J P C = 1 − − . These two states are assumed to contain two strange quarks and two anti-strange quarks, with the flavor symmetry 6 s s ⊗ 6 ¯ s ¯ s ¯ . We consider seven decay channels: ϕ η , ϕ η ′ , ϕ f 0 (980) , ϕ f 1 (1420) , h 1 (1415) η , h 1 (1415) η ′ , and h 1 (1415) f 1 (1420) . Some of these channels are kinematically possible, and we calculate their relative branching ratios through the Fierz rearrangement. Future experimental measurements on these ratios could be useful in determining the nature of the ϕ (2170) and X (2436) . The ϕ (2170) has been observed in the ϕ f 0 (980) , ϕ η , and ϕ η ′ channels, and we propose to further examine it in the h 1 (1415) η channel. Evidences of the X (2436) have been observed in the ϕ f 0 (980) channel, and we propose to verify whether this structure exists or not in the ϕ η , ϕ η ′ , h 1 (1415) η , and h 1 (1415) η ′ channels. [ABSTRACT FROM AUTHOR]

We use the Hawkes process to model the high-frequency price process of 108 stocks in the Chinese stock market, in order to understand the endogeneity of price changes and the mechanism of information processing. Using a piece-wise constant exogenous intensity, we employ non-parametric estimation, residual analysis, and Bayesian Information Criterion (BIC) to determine that a power-law kernel is the most appropriate for our data. We propose the internal branching ratio to represent endogeneity within a finite interval. The branching ratio tends to be higher after the market opens and before the market closes, with a mean value of around 0.81, suggesting significant endogeneity in price changes. In addition, we explore the relationship between branching ratios and stock characteristics using panel regression. Higher branching ratios are associated with lower levels of price efficiency at high, but not low, frequencies. Finally, the branching ratio increases over time without significant impact from COVID-19. [ABSTRACT FROM AUTHOR]

Current study is aimed at evaluating Eu-doped barium-bismuth phosphate glasses as potential visible laser medium operating in red spectral region. Samples with composition x Eu 2 O 3 –20BaO–20Bi 2 O 3 -1.5Al 2 O 3 -(58.5- x)P 2 O 5 (x = 0, 0.5, 1.0, 1.5) were prepared using melt-quenching technique. Physical parameters, such as, density, molar volume, oxygen packing density, rare-earth ion concentration, inter-nuclear distance and field strength were evaluated. Thermal stability of prepared glass samples was observed using Thermogravimetric Analysis (TG). The influence of rare-earth oxide content on glass transition temperature T g , crystallization temperature T c and onset of crystallization temperature T x was studied through Differential Thermal Analysis (DTA). Optical band gap and related optical properties were evaluated from absorption spectrum recorded in the range 225–1000 nm. Judd-Ofelt parameters, branching ratio, radiative lifetime, emission cross-section and other radiative properties were evaluated from photoluminescence emission spectrum in the range 500–750 nm. High value of emission cross-section observed for transition 5D 0 →7F 4 in 0.5-EuBiPBa sample signifies its potential use in the development of visible lasers. [ABSTRACT FROM AUTHOR]

In this paper, I have investigated the two-body pure penguin decays of B 0 → K * 0 K ¯ * 0 and B s 0 → K * 0 K ¯ * 0 , that these were collected with the LHCb detector, and the branching fractions were measured to be B (B 0 → K * 0 K ¯ * 0) = (8.0 ± 0.9 ± 0.4) × 10 − 7 and B (B s 0 → K * 0 K ¯ * 0) = (10.8 ± 2.1 ± 1.5) × 10 − 6 . I have studied these decay modes within the framework of the factorization approach by using three different energy scales; while in calculating the amplitude of these decays, the multiplications of four vectors of the polarization vectors, such as (ε K ¯ * 0 · ε K * 0 ) , (ε K ¯ * 0 · p B (s) ) , and (ε K * 0 · p B (s) ) appear. These parameters have been calculated based on helicity amplitudes (A 0 , A + , A −) ; the results obtained for branching fractions in the μ = mb/2 scale are B (B 0 → K * 0 K ¯ * 0) = (7.1 ± 1.3) × 10 − 7 and B (B s 0 → K * 0 K ¯ * 0) = (10.2 ± 1.9) × 10 − 6 . I have also estimated the fractions of longitudinal polarizations in B 0 → K * 0 K ¯ * 0 and B s 0 → K * 0 K ¯ * 0 decay modes by considering the transverse amplitudes (A ⊥ , A ∥) ; at the μ = mb/2 scale the results are obtained to be f L (B 0 → K * 0 K ¯ * 0) = 0.519 ± 0.067 and f L (B s 0 → K * 0 K ¯ * 0) = 0.419 ± 0.054 , which are comparable to the experimental results, 0.724 ± 0.051 ± 0.016 and 0.694 ± 0.016 ± 0.012, respectively, reported by the LHCb collaboration. [ABSTRACT FROM AUTHOR]

We study the strong decays of the ϕ(2170), along with its possible partner X(2436), as two fully strange tetraquark states of JPC=1−−. These two states are assumed to contain two strange quarks and two anti-strange quarks, with the flavor symmetry 6ss⊗6¯s¯s¯. We consider seven decay channels: ϕη, ϕη′, ϕf0(980), ϕf1(1420), h1(1415)η, h1(1415)η′, and h1(1415)f1(1420). Some of these channels are kinematically possible, and we calculate their relative branching ratios through the Fierz rearrangement. Future experimental measurements on these ratios could be useful in determining the nature of the ϕ(2170) and X(2436). The ϕ(2170) has been observed in the ϕf0(980), ϕη, and ϕη′ channels, and we propose to further examine it in the h1(1415)η channel. Evidences of the X(2436) have been observed in the ϕf0(980) channel, and we propose to verify whether this structure exists or not in the ϕη, ϕη′, h1(1415)η, and h1(1415)η′ channels.

The effect of adding PbF2 to the spectroscopic properties of dysprosium-doped borate-based glasses is studied. The content of PbF2 in the glass is varied from 0 to 50 mol%. X-ray diffraction confirms the amorphous nature of the glass. The Judd–Ofelt theory is applied to evaluate the intensity parameters Ωλ (λ = 1, 2, 3) from the UV-Vis-NIR absorption spectra of glasses. Various radiative parameters are calculated, and the variation of these parameters with different concentrations of lead fluoride is discussed. The fluorescence spectra of glasses are recorded, and it is observed that the fluorescence yield increases as the PbF2 content rises from 0 to 40 mol% but decreases thereafter. The IR absorption spectra of these glasses are also recorded and interpreted in terms of changes in the structure of the glasses. The decay lifetime of the 4F9/2 level of the dysprosium ion is measured from the decay profile and compared with the calculated lifetime. [ABSTRACT FROM AUTHOR]

Heavy neutrinos are usually introduced to accommodate tiny neutrino masses via seesaw mechanism, or to alleviate the cosmology problem, and there may exist charged Higgs which couple to the leptons with different flavors. These two features can appear in the Twin Higgs models. What interests us is that such new particles and interactions may lead to new contributions to the lepton flavor violating processes ℓ i → ℓ j γ and ℓ i → ℓ j ℓ k ℓ l . We find that current experimental data can constrain the parameter spaces and certain lepton flavor violating processes can possibly be tested by the next generation experiments. [ABSTRACT FROM AUTHOR]

Methanol (CH 3 OH) and formaldehyde (HCHO) reacting with nitrogen dioxide (NO 2) contribute to the largest uncertainty for the CH 3 OH/NO x low temperature combustion mechanism. CH 3 OH and NO 2 only undergo H-abstraction reactions, while HCHO + NO 2 involves multiple reaction channels, among which H-abstraction dominates. In the present work, a high level quantum chemical method, CCSD(T)/aug-cc-pVQZ//M06–2X-D3/6-311++G(d,p), was employed to investigate the reaction pathways. The reaction kinetics were explored by RRKM/master equation simulations with multidimensional small-curvature tunneling (SCT) corrections and hindered rotor approximations. The H-abstraction reactions with barriers higher than 20 kcal/mol indicate a nonnegligible quantum tunneling effect even under combustion conditions. Our computations predict the tunneling factors to be 3–4 for the studied reactions at 500 K. A significant tunneling effect is also expected for H-abstraction of large alcohols and aldehydes by NO 2. The computed total rate coefficients show good agreement with previous experimental measurements over narrow ranges of temperature and pressure, ensuring the accuracy of the reported branching ratios covering a wide T, P range for the two reactions. The results of CH 3 OH + NO 2 reveal the dominant role of HONO cis + CH 2 OH. It's also uncovered the dominance of HONO cis + CHO pathway in HCHO + NO 2 under the studied conditions. The detailed reaction kinetics information reported in this work is useful for building rate rules for the mechanisms of other nitrogen-containing alcohol-based fuels. [ABSTRACT FROM AUTHOR]

The mechanistic, thermochemical, and kinetic study of the 4-hydroxy-2-pentanone (4H2P) + OH radical reaction is performed for the first time by employing quantum theoretical calculations. The potential energy diagram was evaluated for five possible reaction pathways at the CCSD(T)/cc-pVTZ//BH&HLYP/cc-pVTZ level of theory. Theoretical rate coefficients of five abstraction pathways are computed as a function of temperature (210–350 K) utilizing the canonical variational transition state theory (CVT) with small-curvature tunneling (SCT). A three-parameter modified Arrhenius equation is used to fit rate coefficients. The thermodynamic quantities like reaction enthalpy and Gibbs free energy are calculated at the BH&HLYP/cc-pVTZ level of theory. According to thermodynamic analysis, the hydrogen abstraction from the –CH group adjacent to the hydroxyl group occurs more favorably and is the dominant pathway with minimum barrier height. The structure–activity relationship is explored by comparing rate coefficients of the titled reaction with the literature values of similar species. The subsequent fate of the alkyl radical (CH3C(O)CH2C·(OH)CH3) is further studied in a NO-rich environment resulting in the formation of acetone, NO2, and oxygen as the major final products. [ABSTRACT FROM AUTHOR]

The ionization data of a neutral molecule are crucial to model the energy deposition and dissociative ionization process. We study theoretically the electron impact ionization process and report on the dissociative ionization cross sections of the tungsten hexafluoride cations invoking the modified-binary-encounter-Bethe model. In this model, the binary-encounter-Bethe model is modified by applying the transformation to the binding energies of the molecular orbitals and then normalizing the partial ionization cross sections of the cations using the branching ratios. The normalization is performed at a particular energy and ensures that the branching ratios of different fragments are summed to unity. The model yielded satisfactory results for both the singly and doubly ionized ions. The approach validates the results of Basner et al. The advantages and limitations of this model are also discussed. This work corroborates the importance of mass spectrometry data in the proper understanding of the ionization process. [ABSTRACT FROM AUTHOR]

Molecular systems including clusters often manifest multiple photodissociation pathways upon absorption of photon energy enough to break down chemical bonds. This certainly raises fundamental questions to chemists: which pathway will be most favored and how can we predict it with precision? To address these issues, we had previously introduced a rather crude but highly simplified and straightforward calculation method, Rice-Ramsperger-Kassel-Marcus (RRKM) calculation method complemented by the concept of extreme loose transition state (eLTS). This approach has proven effective in estimating branching ratios in photodissociation of C 6 H 4 BrCl+. Here, we have extended this method to interpret results in IR photodissociation of (C 6 H 5 NH 2)+-H 2 O–H 2 18O for further evaluation and refinement of this method. We compared branching ratios derived from RRKM-eLTS with those obtained via phase-space theory (PST) to find that our calculation results through RRKM-eLTS were quite in line with the experimental data while those from PST calculation fluctuated significantly depending on the calculation levels and basis sets. This indicates that RRKM-eLTS model not only aligns well with experimental observations giving insights into the relevant rate constants but also intuitively explains these results. We, hereby, suggest that RRKM-eLTS model is a robust and user-friendly method for computing branching ratios, with possible applications to other molecular systems. [Display omitted] • The branching ratio in photodissociation of aniline-water-water-18O cluster cation, (C 6 H 5 NH 2)+-H 2 O–H 2 18O (A+W18W) was determined by tandem mass spectroscopy. • The extremely loose transition state (LTS) model was developed to calculate the branching ratios in unimolecular dissociation reactions. • The RRKM theory with extremely LTS model proved to be successful to estimate the branching ratio in photodissociation. [ABSTRACT FROM AUTHOR]

Terbium-157 was radiochemically extracted from an irradiated tantalum target. Since the resulting material contained a significant impurity of 158Tb, 157Tb was isotopically purified using laser resonance ionization at the RISIKO mass separator in Mainz and then implanted on an aluminum (Al) foil. The implanted 157Tb was measured by two different calibrated gamma-ray spectrometers to determine photon emission rates. After dissolving the Al foil, a high purity 157Tb solution was obtained. The corresponding activity concentration was determined with a low relative uncertainty of 0.52% through a combination of liquid scintillation counting using the TDCR method and 4π(X,e)(LS)-(X,γ)(CeBr 3) coincidence counting. By combining the results from all measurement techniques, emission intensities for K X-rays and gamma-rays were derived and found to be 16.05(31)% and 0.0064(2)%, respectively. The probability for K electron capture of the first forbidden non-unique transition to the ground state was determined to be 17.16(35)%. The probabilities for the electron-capture branch to the excited level and the ground state were found to be 0.084(4)% and 99.916(4)%, respectively. A Q + value of 60.23(18) keV was estimated based on simplified BetaShape calculations, assuming an allowed transition. • Gamma-ray spectrometry to determine photon emission rates. • Activity determination by liquid scintillation counting using the TDCR method. • Activity measurement by 4π(X,e) (LS)-(X,γ) (CeBr 3) coincidence counting. • Determination of gamma-ray and K X-ray emission probabilities. • Determination of branching ratio, K capture probability, and transition energy Q +. [ABSTRACT FROM AUTHOR]

Two heteroleptic homo-dinuclear complexes of Dy(III) and Sm(III) with pyrazine (pyz) as spacer ligand [Ln(TFPB) 3 (μ-pyz)Ln(TFPB) 3 ], along with their mononuclear analogue [Ln(TFPB) 3 (pyz) 2 ] were synthesized and characterized. Diketone TFPB (4,4,4-trifluoro-1-phenyl-1,3-butanedione) was incorporated as main ligand. NMR analysis depicted single peak for pyz protons for dinuclear complexes and two for mononuclear ones, which confirmed the bridging nature of pyz in former complexes. UV spectra revealed two absorption bands despite of the different metal ion and nuclearity of complex, suggesting the absorption of UV-radiation by coordinated moieties inspite of the metal ion involved. The emission spectra exhibited significant intensity of yellow and orange-red peaks for Dy(III) and Sm(III) complexes, respectively, indicating effective sensitization of metal center. The enhanced emission intensity observed in dinuclear Sm-complexes, compared to their mononuclear counterparts, indicates a synergistic effect of the two metal ions on the overall emission properties, rather than a mere additive effect that would be expected from two independent mononuclear units. The photoluminescent properties of synthesized complexes were examined and discussed, suggesting potential applications in display devices. The Correlated Color Temperature (CCT) of these complexes falls within a range suitable for warm light sources and the highest branching ratio observed for 4G 5/2 → 6H 9/2 (for Sm3+ ion) and 4F 9/2 → 6H 13/2 (for Dy3+ ion) transitions suggests potential application in laser amplification. The alignment between band gap measurements obtained from UV and CV analyses highlight the possibility of employing these complexes in semiconductor technologies. • Analyzed solid state luminescence in Sm(III) and Dy(III)-complexes with pyrazine and TFPB ligands. • Explored dual role of pyrazine: Bridging and monodentate behaviours. • Enhanced luminescence intensity in dinuclear Sm-complexes: Evidence for participation of both metal ions in radiative relaxation. • Single 1H NMR signal: Validating bridging role of pyrazine in SmD and DyD. [ABSTRACT FROM AUTHOR]

In this paper, the decay of the meson into two vector mesons and is investigated.The first observation of the decay was reported in 2017 by LHCb collaboration, they have obtained the value of B () = (5. 01 ± 053 ± 0.27 ± 0.06)×10-4. In this study, the Feynman diagram of decay is drawn based on the standard model. In particular this diagram shows that the decay consists of tree-exchange internal w-emission graph and penguin- suppressed graph. The coefficients of a2, a3, a5 and a7 are calculated in the NLO scale. The branching ratio is calculated using the QCD factorization method, numerical values in the NLO (at mb scale) scheme is 5.33×10-4, for which are in good agreement with the experimental results. The more calculations accuracy increases, the b quark mass scales come down corresponding to that. The best answer close to the experimental value is in NLO scheme at mb scale of QCDF approach.‎

Root branching and mycorrhizal symbioses are two major mechanisms for soil resource acquisition by trees. Understanding the relationship between these two mechanisms and their responses to varied environmental conditions is crucial for predicting the responses of foraging strategies of roots to environmental changes. This study was conducted in 11 Chinese fir (Cunninghamia lanceolata) plantations distributed in different environmental conditions in Subtropical China to assess the relationship between root tip traits related to nutrient foraging (branching ratio of 1st-order roots to 2nd-order roots, arbuscular mycorrhizal (AM) colonization) and their environmental variables, including mean annual precipitation (MAP), mean annual temperature (MAT), soil C, soil N, soil P, and soil pH. Root branching was more sensitive to environmental conditions than mycorrhizal symbioses. The branching ratio and AM colonization of Chinese fir were significantly related to several environmental variables. The branching ratios were positively correlated with MAT, but negatively correlated with soil C, soil N, and soil pH (P < 0.05), suggesting that harsh environmental conditions can promote absorptive root branching. To our surprise, the AM colonization of absorptive roots was not as sensitive to environmental factors as branching ratio. However, the AM colonization of absorptive roots was positively correlated with soil pH (P < 0.1), indicating that soil acidity controls mycorrhizal symbioses. Moreover, the branching ratio was significantly negatively correlated with AM colonization (P < 0.05). Our results confirmed that environmental conditions significantly regulate fine root branching and its mycorrhizal symbioses, but with different controlling variables. The negatively correlated relationship of branching ratio and AM colonization shows that environmental factors regulate absorptive root traits in different ways. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the charged Higgs boson decay in the context of the type-II two-Higgs-doublet model in the presence of a circularly polarized electromagnetic field of laser radiation. The calculations are performed by adopting the Furry picture approach of non-perturbative interactions with the external electromagnetic field. Using the method of exact solutions for charged particles states in the presence of a circularly polarized electromagnetic wave field and evaluating the S-matrix elements, an exact analytic expression is derived for the decay width of leptonic, hadronic and bosonic decay modes. The branching ratios of different decay modes with multiple photon emission and absorption from the laser beam are analyzed and found to be dramatically modified in the region of superstrong fields. The dependencies of the decay width on the laser field strength and frequency are also examined. The results obtained may be interesting for future experimental and theoretical investigations.

The H+CH3OH reaction, which plays an important role in combustion and the interstellar medium, presents a prototypical system with multiple channels. In this work, mode specific dynamics of different product channels is investigated theoretically on a recently developed reliable potential energy surface based on a large number of data points calculated at the level of UCCSD(T)-F12a/AVTZ. It has been demonstrated that vibrational excitations of the O-H stretching motion, the torsional motion, the C-H stretching vibrations, show different influences on the four product channels, H2+CH3O, H2+CH2OH, H2O+CH3, and H+CH3OH. This work is helpful for understanding the mode-specific dynamics and controlling the competition for complicated reactions with multiple product channels. [ABSTRACT FROM AUTHOR]

The product branching ratio between different products in multichannel reactions is as important as the over-all rate of reaction, both in terms of practical applications (e.g. models of combustion or atmosphere chemistry) in understanding the fundamental mechanisms of such chemical reactions. A global ground state potential energy surface for the dissociation reaction of deuterated alkyl halide CD3CH2F was computed at the CCSD(T)/CBS//B3LYP/aug-cc-pVDZ level of theory for all species. The decomposition of CD3CH2F is controversial concerning C−F bond dissociation reaction and molecular (HF, DF, H2, D2, HD) elimination reaction. Rice-Ramsperger-Kassel-Marcus (RRKM) calculations were applied to compute the rate constants for individual reaction steps and the relative product branching ratios for the dissociation products were calculated using the steady-state approach. At the different energies studied, the RRKM method predicts that the main channel for DF or HF elimination from 1,2-elimination of CD3CH2F is through a four-center transition state, whereas D2 or H2 elimination from 1,1-elimination of CD3CH2F occurs through a direct three-center elimination. At 266, 248, and 193 nm photodissociation, the main product CD2CH2+DF branching ratios are computed to be 96.57%, 91.47%, and 48.52%, respectively; however, at 157 nm photodissociation, the product branching ratio is computed to be 16.11%. Based on these transition state structures and energies, the following photodissociation mechanisms are suggested: at 266, 248, 193 nm, CD3CH2F→absorption of a photon→TS5→the formation of the major product CD2CH2+DF; at 157 nm, CD3CH2F→absorption of a photon→D/F interchange of TS1→CDH2CDF→H/F interchange of TS2→CHD2CHDF→the formation of the major product CHD2+CHDF. [ABSTRACT FROM AUTHOR]

This study presents the first high-temperature measurements of cyclopentene + OH → k 1 Products reaction over 856 – 1258 K and 1.03 – 4.33 bar. The determined rate coefficients of k 1 exhibited Arrhenius temperature dependence with an activation energy ∼ 3.3 k cal mol−1 and negligible pressure dependence. Rate coefficients of OH + cyclopentene are faster than OH + 1-pentene but comparable to OH + 2-pentene, highlighting the significance of allylic C H bonds in these reactions. At 1258 K, our rate coefficient is ∼ 30 % slower than the average room-temperature measurement, indicating the role of OH-addition pathways at low temperatures. Site-specific rate coefficients and branching ratios are determined, with H-abstraction at the allylic C H site accounting for ∼68 % of the reaction and alkylic C H bond contributing ∼22 %. Our measured k 1 may be given as (unit: cm3molecule−1s−1): k 1 = 1.64 × 10 − 10 e (− 1660 T) Cyclopentene decomposition reaction (cyclopentene → k 2 cyclopentadiene + H 2) is studied over 1186–1472 K and 1.17 – 1.38 bar. Time-resolved yields of the product, cyclopentadiene, are monitored using a sensitive UV laser diagnostic near 220 nm. Absorption cross-sections of cyclopentadiene, measured in two separate mixtures, showed weak positive temperature dependence (8.7 – 9.8 × 10−18 cm2molecule−1) over 961 – 1326 K. Our rate coefficients of k 2 exhibited a positive Arrhenius temperature dependence with an activation energy of ∼ 54.7 k cal mol−1. At 1300 K, the decomposition of cyclopentene proceeds 5.5 and 28 times faster than that of cyclopentadiene and cyclopentane, respectively. Our measured k 2 may be expressed as (unit: s−1): k 2 = 2.55 × 10 12 e (− 27 , 527.6 T) The pentagonal structure of cyclopentene influences its H-abstraction and decomposition reactions distinctively. While H-abstraction by OH follows a mechanism akin to cyclohexene and linear alkenes, with comparable rate coefficients at allylic C H bonds, the penta-ring structure significantly impacts the decomposition mechanism. Cyclopentene decomposition predominantly produces cyclopentadiene and H 2 in a ring-conserving manner, differing from the cleavage of allylic-alkylic C C bonds in the decompositions of 1-alkenes and cyclohexene. [Display omitted] [ABSTRACT FROM AUTHOR]

The study of the brain criticality hypothesis has been going on for about 20 years, various models and methods have been developed for probing this field, together with large amounts of controversial experimental findings. However, no standardized protocol of analysis has been established so far. Therefore, hoping to make some contributions to standardization of such analysis, we review several available tools used for estimating the criticality of the brain in this paper. [ABSTRACT FROM AUTHOR]

We construct a 'reflexivity' index to measure the activity generated endogenously within a market for cryptocurrencies. For this purpose, we fit a univariate self-exciting Hawkes process with two classes of parametric kernels to high-frequency trading data. A parsimonious model of both endogenous and exogenous dynamics enables a direct comparison with exchanges for traditional asset classes, in terms of identified branching ratios. We also formulate a 'Hawkes disorder problem,' as generalization of the established Poisson disorder problem, and provide a simulation-based approach to determining an optimal observation horizon. Our analysis suggests that Bitcoin mid-price dynamics feature long-memory properties, well explained by the power-law kernel, at a level of criticality similar to fiat-currency markets. [ABSTRACT FROM AUTHOR]

The study of the brain criticality hypothesis has been going on for about 20 years, various models and methods have been developed for probing this field, together with large amounts of controversial experimental findings. However, no standardized protocol of analysis has been established so far. Therefore, hoping to make some contributions to standardization of such analysis, we review several available tools used for estimating the criticality of the brain in this paper.

We study the three-body baryonic decay B ̄ 0 → Λ c + p ̄ π 0 based on the factorization approach. The most important Feynman diagrams for this decay mode are factorizable and non-factorizable contributions, so that the former plays the key role in the decay amplitude and the latter affects the amplitude coefficient a2. We calculate the decay branching ratio for some values of a2 in the range of 0.16 − 0.40 and we find that the value of a2 = 0.17 leads us to the result of (1.50 ± 0.21) × 10− 4 which evidently agrees with the experimental result (1.55 ± 0.17 ± 0.08) × 10− 4 reported by BABAR. [ABSTRACT FROM AUTHOR]

The reactions between ground-state H 2 + (X 2 Σ g + (v = 0 , J = 0)) and D 2 forming HD 2 + + H and H 2 D + + D were investigated in the range of collision energies E coll between E coll / k B = 0 and 10 K using a merged-beam approach. The reaction rates measured experimentally are compared to those obtained for the reaction between H 2 + and H 2 forming H 3 + + H under similar experimental conditions. Below 1 K, a clear enhancement of the reaction rate coefficient compared to the Langevin rate measured at higher collision energies was observed in both reaction systems. This enhancement is interpreted as originating from the interaction between the charge of H 2 + and the quadrupole of para D 2 and ortho H 2 molecules in the J = 1 rotational level. The enhancement of the reaction with D 2 was found to be significantly less than that of the reaction with H 2 , reflecting the relative population of the J = 1 rotational level of H 2 (75%) and D 2 (33%) in natural samples at low temperatures. Simulations of the experimental results based on the theoretical predictions of the reaction cross sections by Dashevskaya et al. [J. Chem. Phys. 145, 244315 (2016)] reveal agreement within the experimental uncertainties. The branching ratio η of the reaction involving H 2 + and D 2 and forming H 2 D + and D ( η = [ H 2 D + ] [ H 2 D + ] + [ H D 2 + ] ) near E coll = 0 was determined to be 0.341(15). Time-of-flight measurements of the velocity distributions of the reaction products are compatible with an isotropic product emission with an average total kinetic energy of 0.45(5) eV for both channels, representing about 30% of the total energy released by the reaction. [ABSTRACT FROM AUTHOR]

The ionization data of a neutral molecule are crucial to model the energy deposition and dissociative ionization process. We study theoretically the electron impact ionization process and report on the dissociative ionization cross sections of the tungsten hexafluoride cations invoking the modified-binary-encounter-Bethe model. In this model, the binary-encounter-Bethe model is modified by applying the transformation to the binding energies of the molecular orbitals and then normalizing the partial ionization cross sections of the cations using the branching ratios. The normalization is performed at a particular energy and ensures that the branching ratios of different fragments are summed to unity. The model yielded satisfactory results for both the singly and doubly ionized ions. The approach validates the results of Basner et al. The advantages and limitations of this model are also discussed. This work corroborates the importance of mass spectrometry data in the proper understanding of the ionization process.

The branching ratio method is usually used to evaluate the optical thinness conditions in laser-generated plasmas, which are important for the application of analytical methods such calibration free laser induced breakdown spectroscopy (CF-LIBS). In this communication, we warn on the possibility that in some circumstances, the branching-ratio method might give results close to the one characterizing optically thin plasma conditions, even in the presence of a substantial self-absorption for the transitions considered. Graphical Abstract [ABSTRACT FROM AUTHOR]

The gas-phase kinetics of phenyl radical (·C6H5) with ethyl formate (HCO2Et, EF) was investigated experimentally using ultrasensitive laser-based cavity ring-down spectroscopy (CRDS). Phenyl radicals were generated by photolyzing nitrosobenzene (C6H5NO) at 248 nm and thereby probed at 504.8 nm. The rate coefficients for the (phenyl radical + EF) reaction were investigated between the temperatures of 260 and 361 K and at a pressure of 61 Torr with nitrogen (N2) as diluent. The temperature-dependent Arrhenius expression for the test reaction was obtained as: k phenyl + EF Expt , 260 - 361 K =(1.20 ± 0.16) × 10–13 exp[−(435.6 ± 50.0)/T] cm3 molecule−1 s−1 and the rate coefficient at room temperature was measured out to be: k phenyl + EF Expt , 298 K =(4.54 ± 0.42) × 10–14 cm3 molecule−1 s−1. The effects of pressure and laser fluence on the kinetics of the test reaction were found to be negligible within the experimental uncertainties. To complement the experimental findings, kinetics for the reaction of phenyl radicals with EF was investigated theoretically using Canonical Variational Transition State Theory (CVT) with Small Curvature Tunnelling (SCT) at CCSD(T)/cc-pVDZ//B3LYP/6–31 + G(d,p) level of theory in the temperatures between 200 and 400 K. The theoretically calculated rate coefficients for the title reaction were expressed in the Arrhenius form as: k phenyl + EF Theory , 200 - 400 K = (1.48 ± 0.56) × 10–38 × T8.47 × exp[(2431.3 ± 322.0)/T] cm3 molecule−1 s−1 and the corresponding rate coefficient at room temperature was calculated to be: k phenyl + EF Theory , 298 K = 4.91 × 10–14 cm3 molecule−1 s−1. A very good agreement was observed between the experimentally measured and theoretically calculated rate coefficients at 298 K. Thermochemical parameters as well as branching ratios for the reaction of (phenyl radical + EF) are also discussed in this manuscript. [ABSTRACT FROM AUTHOR]

Novel oxyfluoride glass having composition 10NaF- (59-x)B 2 O 3 - xGd 2 O 3 – 30Bi 2 O 3 - 1Sm 2 O 3 has been synthesized by melt quenching approach. The amorphous nature of the glass was confirmed by the X-ray diffraction pattern. Raman and infrared spectroscopy confirm the presence of BO 3 , BO 4 and BiO 6 units. Photoluminescence studies suggest that the samples are capable of emitting intense light in the reddish-orange region. As Judd-Ofelt parameters follow the Ω 4 >Ω 2 >Ω 6 trend, with improving asymmetry between Samarium ions and ligands. Additionally, the role of Gd 2 O 3 on the emission spectra of Sm3+ is also witnessed in the X-ray luminescence emission spectra. The decay time measurement of the prepared glass samples is performed to explore the applicability of the samples in lighting devices. Further, the thermal sensing capability was examined by using a luminescence intensity ratio related to the two different electronic transitions. These results proposed that prepared glass can be used for lighting devices, temperature sensing and high-energy scintillators. • Novel NaF– B 2 O 3 - Gd 2 O 3 – Bi 2 O 3 - Sm 2 O 3 glass matrix were synthesized. • Judd- Ofelt parameter follows Ω 4 >Ω 2 >Ω 6 trend. • As 4G 5/2 → 6H 7/2 transition exhibits a higher values of branching ratio and stimulated emission cross-section. • Optimum concentration of Gd 2 O 3 was observed at 5.0 mol%. [ABSTRACT FROM AUTHOR]

Naphthalene, the most abundant polycyclic aromatic hydrocarbon in the atmosphere, significantly influences OH consumption and secondary organic aerosol (SOA) formation. Naphthoquinone (NQ) is a significant contributor to ring-retaining SOA from naphthalene degradation, impacting the redox properties and toxicity of ambient particles. However, inconsistencies persist regarding concentrations of its isomers, 1,2-NQ and 1,4-NQ. In present work, our theoretical investigation into naphthalene's reaction with OH and subsequent oxygenation unveils their role in SOA formation. The reaction kinetics of initial OH and subsequent O 2 oxidation was extensively studied using high-level quantum chemical methods (DLPNO-CCSD(T)/aug-ccpVQZ//M052x-D3/6–311++G(d,p)) combined with RRKM/master equation simulations. The reactions mainly proceed through electrophilic addition and abstraction from the aromatic ring. The total rate coefficient of naphthalene + OH at 300 K and 1 atm from our calculation (7.2 × 10−12 cm3 molecule−1 s−1) agrees well with previous measurements (∼1 × 10−11 cm3 molecule−1 s−1). The computed branching ratios facilitate accurate product yield determination. The largest yield of 1-hydroxynaphthalen-1-yl radical (add1) producing the major precursor of RO 2 is computed to be 93.8 % in the ambient environment. Our calculated total rate coefficient (5.2 × 10−16 cm3 molecule−1 s−1) for add1 + O 2 closely matches that of limited experimental data (8.0 × 10−16 cm3 molecule−1 s−1). Peroxy radicals (RO 2) generated from add1 + O 2 include 4- cis/trans -(1-hydroxynaphthalen-1-yl)-peroxy radical (add1-4OO add- cis/trans , 66.0 %/17.5 %), 2- cis/trans -(1-hydroxynaphthalen-1-yl)-peroxy radical (add1-2OO add- cis/trans , 10.3 %/6.3 %). Regarding the debated predominance of 1,4-NQ (corresponding to the parent RO 2 , i.e., add1-4OO add- cis/trans) and 1,2-NQ (corresponding to the parent RO 2 , i.e., add1-2OO add- cis/trans) in the atmosphere, our findings substantiate the dominance of 1,4-NQ. This study also indicates potential weakening of 1,4-NQ's dominance due to competition from decomposition reactions of add1-4OO add- cis/trans and add1-2OO add- cis/trans. Precise reaction kinetics data are essential for characterizing SOA transformation derived from naphthalene and assessing their climatic impacts within modeling frameworks. [Display omitted] • The reactions of naphthalene + OH and subsequent O 2 oxidation mainly proceed through addition and abstraction pathways. • The computed total k of OH and subsequent O 2 reaction are 7.2 × 10−12 and 5.2 × 10−16 cm3 molecule−1 s−1 at 300 K, 1 atm. • The add1 (93.8%) and add1-4OO add- cis (66.0%) are the predominant products of naphthalene + OH and subsequent O 2 oxidation. • The formation of 1,4-naphthoquinone (1,4-NQ) is more favorable than that of 1,2-NQ during naphthalene degradation. • The dominant role of 1,4-NQ is weakened due to the competition from the decomposition reactions of 1,4-RO 2 and 1,2- RO 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Europium (III) complexes were synthesized using solution precipitation method. • Optical properties indicate utility of these complexes in luminescent devices. • Judd-Ofelt, radiative properties, band gap, Urbach and lasing properties were calculated experimentally and theoretically. • Band gap values indicate application of these complexes in semiconductor devices. Six novel red photoluminscent eight co–ordinate Eu3+ complexes were synthesized by using 6–Chloro–chromone–3–aldehyde as main ligand (L) which are represented as [Eu(L 3).X] where X is 2H 2 O (C1), 1,10-Phenanthroline (C2), Neocuproine (C3), 2,2′-Bipyridyls (C4), 5,6-Dimethyl-1,10-Phenanthroline (C5), Bathophenanthroline (C6). The above complexes synthesized by solution precipitation method were characterized by elemental analysis, EDAX analyzer to describes the presence of C, H, O, Cl and Eu. Scanning electron microscope (SEM) to indicates semicrystalline nature of complexes, transmission electron microscopy (TEM) to describes size of complexes lies in 55 to 60 nm, nuclear magnetic resonance (1H NMR) and infrared radiation (FT-IR) to describe the coordination between Eu3+ ion and ligand and ancillary ligands. Thermo-gravimetric analysis (TGA/DTA) tells that complexes are stable upto 290 °C, and photoluminescence (PL) analysis. By using PL data and luminescence decay time (τ), the transition rates, quantum efficiency and the Judd-Ofelt intensity parameters were determined. The luminescence emission spectra for complexes in both states show an intense emission peak (5D 0 →7F 2) at 614 nm (solid) and at 613 nm (solution) of Eu3+ which is responsible to make them an efficient red color emitter in luminescent devices. These complexes are applicable in light emitting devices, traffic signals and home appliances. Percentage branching ratio (β r) and CIE color coordinates value of all synthesized complexes in both states were analyzed. The value of Percentage branching ratio (β r) is 79.92–84.65 % in solid state whereas in solution state the value lies in range 49.37–75.37 % and values of percentage branching ratio (β r) suggests that these complexes are used in lasers and radars systems. The color purity [CP(%)] values are found to be 92.96–94.31 % in solid and 81.24–93.70 % in solution. The band gap is calculated and found to be in the range of 3.7–3.9 eV and used in semiconductor and electroluminescent devices. The complexes (C1–C6) are considered as warm light source because the complexes heaving values of correlated color temperature (CCT) in between 2785 and 3024 K in solid state and 1734 to 2912 K in solution state, which can be efficiently used in LEDs present in hotels, lounges and in many home appliances. The above investigation suggests that synthesized complexes are significant emitters with broad area of utility in laser, electroluminescent materials and display devices. [ABSTRACT FROM AUTHOR]