Decay Ratio Research Articles

Status of the NA62 Experiment

The decay $ {K^ + } \to {\pi ^ + }v\bar v $, with a very precisely predicted branching ratio of less than 10−10 in the Standard Model framework, is one of the best candidates to reveal indirect effects of new physics at the highest mass scales. The NA62 experiment at CERN SPS is designed to measure the branching ratio of such decay with a decay-in-flight technique, novel for this channel. The main goal of NA62 is to measure such Branching Ratio of $ {K^ + } \to {\pi ^ + }v\bar v $ with an accuracy better than 20%. This will be achieved by collecting up to 100 $ {K^ + } \to {\pi ^ + }v\bar v $ events with a background contamination at the level of 10%. The NA62 detector was commissioned in 2014 and 2015 and the experiment took physics data from 2015 to 2018. NA62 has already published the result of the 2016 data analysis. The 2017 data analysis is in progress, the single event sensitivity reached and the evaluation of the main backgrounds will be shown in this contribution.

Design and Implementation of a Tuning-Matching Framework for a High-Sensitivity Broad Band Proton Precession Magnetometer Sensing Coil

The proton precession magnetometer (PPM) is always employed for geomagnetic observation, magnetic anomaly detection, etc., while the tuning performance of the PPM determines the signal-to-noise ratio (SNR) of the free induction decay (FID) signal output from the sensing coil. A tuned circuit was always used for the PPM sensing coil because of its narrow-band characteristic and high sensitivity. However, the FID signals might be distorted by the narrow bandwidth, which influences the PPM’s measurement accuracy for the geomagnetic field. To address this problem, we propose a tuning-matching framework consisting of an adjustable tuning capacitor network (ATCN) in parallel with a $\pi $ -type LC band-pass filter (LCBF), dubbed ATCN-LCBF. The equivalent circuit of the ATCN-LCBF are investigated and the corresponding electrical parameters are theoretically calculated. Consequently, the proposed ATCN-LCBF is conducted with a bandwidth of 3500 Hz, a pass-band gain of 5 dB, and an average noise floor of 1.67 nV/Hz1/2. The field experimental results demonstrate that the ATCN-LCBF can not only enhance the strength of the FID signal but also suppress the external noises, improving the signal detection performance of the PPM in a scenario with strong interference.

Recycling materials from degraded lithium-ion batteries for Na-ion storage

In order to improve capacity decay and poor rate capability of CoS2 electrode, ingenious integration of both advanced material design and highly efficient electrode structure is crucial and desirable. Herein, we demonstrate a novel strategy to achieve this purpose by designing and synthesizing a single-walled carbon nanotube/reduced Graphene-oxides/CoS2@graphitic carbon (SWCNT-rGO-CoS2-C) nanocomposite membrane with high mechanical flexibility and Na-ion storage properties, in which CoS2–C composite with core-shell structure was synthesized utilizing spent Li-ion batteries materials as precursors through a facile heat-treatment method. Benefiting from the synergistic effect of CoS2 nanoparticles embedding into the graphitic carbon and flexible membrane electrode with 3D network architecture, the SWCNT-rGO-CoS2-C electrode with high content of active material (55.37 wt% in the whole electrode including current collector) exhibits improved cycling stability (709.9 mAh g−1 after 1000 cycles with a small capacity decay ratio of 0.00949% at 3000 mA g−1) and superior rate capability (discharging specific capacity of 533.3 mAh g−1 at 20000 mA g−1), which is proved to be ascribed to the partial pseudocapacitive behaviors during the sodiation and desodiation process. This approach is not only mitigating environment pollution and reducing waste of resources, but also achieving the energy recycling, and holds great application prospects in wearable and lightweight energy storage devices.

Effects of universal extra dimensions on top-quark electromagnetic interactions

Universal extra dimensions, presumably observable at some high-energy scale, would modify low-energy observables, being particularly relevant for physical processes forbidden at tree level by the Standard Model. We address the Kaluza–Klein contributions from the 5-dimensional Standard Model to the anomalous magnetic moment and to branching ratios of electromagnetic decays of the top quark. In accordance with present bounds on the compactification scale, contributions to both quantities are found to be at least 3 orders of magnitude below Standard-Model predictions.

Field Measurement and Research on Environmental Vibration due to Subway Systems: A Case Study in Eastern China

With the rapid development of subway systems, the negative environmental impacts of vibration induced by subways has gradually become a research hotspot. For the purpose of developing predictive models of vibration and designing effective vibration mitigation systems, continuous field dynamic measurements were conducted simultaneously in a subway tunnel, ground, and building in eastern China, the most prosperous region in China. The characteristics of vibration transmission and attenuation induced by subway were analyzed by statistical analysis of large amounts of measurement data. The results showed that most prominent and visible attenuation of vibration is from the track to the ballast bed in the tunnel, where the ground-borne vibration would quickly decrease exponentially with distance. The results also showed that the measured attenuation value of indoor vibration was approximate 0.76 dB on average between each floor. Moreover, the decay ratio of the vibration increased with the increase in the frequency range. Based on these findings, construction gauge of 20–25 m outside of the tunnel is recommended. In addition, reducing the vibration source excitation intensity is the most effective vibration isolation method, especially by track structural transformation.

Dual incremental fuzzy schemes for frequent itemsets discovery in streaming numeric data

Discovering frequent itemsets is essential for finding association rules, yet too computational expensive using existing algorithms. It is even more challenging to find frequent itemsets upon streaming numeric data. The streaming characteristic leads to a challenge that streaming numeric data cannot be scanned repetitively. The numeric characteristic requires that streaming numeric data should be pre-processed into itemsets, e.g., fuzzy-set methods can transform numeric data into itemsets with non-integer membership values. This leads to a challenge that the frequency of itemsets are usually not integer. To overcome such challenges, fast methods and stream processing methods have been applied. However, the existing algorithms usually either still need to re-visit some previous data multiple times, or cannot count non-integer frequencies. Those existing algorithms re-visiting some previous data have to sacrifice large memory spaces to cache those previous data to avoid repetitive scanning. When dealing with big streaming data nowadays, such large-memory requirement often goes beyond the capacity of many computers. Those existing algorithms unable to count non-integer frequencies would be very inaccurate in estimating the non-integer frequencies of frequent itemsets if used with integer approximation of frequency-counting.To solve the aforementioned issues, in this paper we propose two incremental schemes for frequent itemsets discovery that are capable to work efficiently with streaming numeric data. In particular, they are able to count non-integer frequency without re-visiting any previous data. The key of our schemes to the benefits in efficiency is to extract essential statistics that would occupy much less memory than the raw data do for the ongoing streaming data. This grants the advantages of our schemes 1) allowing non-integer counting and thus natural integration with a fuzzy-set discretization method to boost robustness and anti-noise capability for numeric data, 2) enabling the design of a decay ratio for different data distributions, which can be adapted for three general stream models: landmark, damped and sliding windows, and 3) achieving highly-accurate fuzzy-item-sets discovery with efficient stream-processing.Experimental studies demonstrate the efficiency and effectiveness of our dual schemes with both synthetic and real-world datasets.

Exergy analysis of supersonic steam jet condensed into subcooled water

Exergy analysis of supersonic steam jet condensed into subcooled water was conducted via a numerical method. A thermal phase-change model was employed by Ansys, and considering turbulence interaction and turbulent dispersion force, three-dimensional simulations were conducted to simulate supersonic steam jet at different test conditions. Results indicated that the exergy flow of steam jet was mainly affected by water temperature and inlet steam pressure. The total physical exergy flow decayed monotonically due to the significant irreversible losses caused by heat and momentum transfer. For under-expanded supersonic steam jet, the peak distributions of steam kinetic exergy flow were obtained. The peak distributions of the water enthalpy exergy flow were also obtained at low water temperatures (293.15 K and 303.15 K). In addition, water temperature was found to be the main factor in the damping-energy properties of the supersonic steam jet. The damping-energy ratio and decay rate of the time-averaged kinetic energy decreased with the increase in water temperature, and a correlation was proposed to predict the time-averaged kinetic energy decay ratio.

Phenomenology of the partially aligned 2HDM with leptonic meson decays

In this paper we present a phenomenological analysis of the Partially Aligned Two Higgs Doublet Model (PA-2HDM) by using leptonic decays of mesons and [Formula: see text]–[Formula: see text] mixing. We focus our attention in a scenario where the leading contribution to FCNC is given by the tree-level interaction with the light pseudoscalar [Formula: see text] ([Formula: see text] GeV). We show how an underlying flavor symmetry controls FCNC in the quark and lepton couplings with the pseudoscalar, without alignment between Yukawa matrices. Upper bounds on the free parameters are calculated in the context of the leptonic decays [Formula: see text] and [Formula: see text] and [Formula: see text] mixing. Also, our assumptions imply that bounds on New Physics contribution in the quark sector coming from [Formula: see text] mixing impose an upper bound on the parameters for the leptonic sector. Finally we give predictions of branching ratios for leptonic decay of mesons with FCNC and LFV.

‘후지’ 사과의 품질에 대한 강제송풍 예냉처리와 MA 필름 포장의 효과

This study was carried out to find a method of pretreatment before storage to improve the shelf life of apples. Fuji apple was pretreated with forced air precooling and pretreated with neutral water and packed in a functional MA film and stored for 18 weeks at 0℃ to investigate changes in quality such as weight, hardness, decay rate, titratable acidity and vitamin C. The weight loss of apple packed functional MA film was higher than that of control, weight loss of control was 6.3% and that of functional MA films were 0.3-0.9%. The change of hardness and titratable acidity was also lower than that of control. The decay ratio of apple packed with functional MA films were 1.7-1.4% but that of control was 5.3%, the decay ratio of control was higher than those of functional MA film. Vitamin C also showed little change in MA film packaging after pretreatment. Therefore, when the apple is stored for a long period, it is effective to maintain quality of Fuji apple by forced air precooling method or precooling to low temperature with neutral water and storage in MA film packaging.

COMBINED TREATMENTS OF MODIFIED ATMOSPHERE PACKAGING WITH AMINOETHOXYVINYLGLYCINE MAINTAINED FRUIT QUALITY IN SWEET CHERRY THROUGHOUT COLD STORAGE AND SHELF LIFE

The effects of combined aminoethoxyvinylglycine (AVG) and modified atmosphere packaging (MAP) treatments on quality attributes of ‘0900 Ziraat’ sweet cherry fruit during the cold storage and shelf life were investigated in this study. Significantly lower weight loss and decay ratios were observed in all treatments throughout the cold storage period as compared to the control. A similar case was also observed referring to the shelf life. MAP treatments were found to be more effective in retarding the weight loss and decay ratio. Higher hue angle values were measured from AVG-treated fruit at harvest. Similarly, hue angle of AVG and MAP-treated fruit were also higher than for the control in all periods of cold storage and on the 7th and 21st day of shelf life. AVG-treated fruit had higher firmness values than the control at harvest. However, higher firmness values were measured from MAP-treated fruit during the cold storage and shelf life. At the end of cold storage, lower SSC and higher titratable acidity values were observed in AVG and MAP-treated fruit than in the control. AVG + MAP treatments yielded significantly higher vitamin C, total phenolics and antioxidant activity values than the control. Contrarily, the control fruit had significantly higher total monomeric anthocyanin than the other treatments. Based on current findings, it was concluded that combined AVG + MAP treatments could be used as a beneficial tool to maintain the quality of sweet cherry fruit throughout the cold storage and shelf life.

Time Series Analysis for BWR Stability Studies

Analysis of the power time series evolution is used to investigate a stable or unstable process after the disturbance in a light water reactor of the boiling water reactor (BWR) type. Several different methodologies are currently used and the uncertainties of the various approaches are in some cases very different. In this work, the time series model known as the Autoregressive Moving Average model was used to calculate the decay ratio (DR), and the natural frequency (NF) due to power oscillations in a BWR. The method consists of locating the appropriate dominant pole of the transfer function. The autoregressive methods are quite often used to study the stability of BWR reactors. In this work the Box-Cox transformation is implemented to stabilize the variances of the power signals in order to maintain the linear assumptions that the calculation of DR and NF needs; that is, to correct biases in the distribution of errors to stabilize the variance and mainly so that the signal approaches a linear behavior. The MATLAB code was used for this purpose. This work also presents a nonlinear analysis of the power series, determining the values of the largest Lyapunov exponents with Rosenstein’s algorithm in order to analyze the stability of the system. The results of the DR and NF calculated by the used methodology are very close to the values obtained in the benchmark.

Testing SU(3) flavor symmetry in semileptonic and two-body nonleptonic decays of hyperons

The semileptonic decays and two-body nonleptonic decays of light baryon octet ($T_8$) and decuplet ($T_{10}$) consisting of light $u,d,s$ quarks are studied with the SU(3) flavor symmetry in this work. We obtain the amplitude relations between different decay modes by the SU(3) irreducible representation approach, and then predict relevant branching ratios by present experimental data within $1 \sigma$ error. We find that the predictions for all branching ratios except $\mathcal{B}(\Xi\rightarrow \Lambda^0\pi)$ and $\mathcal{B}(\Xi^*\rightarrow \Xi\pi)$ are in good agreement with present experimental data, that implies the neglected $C_+$ terms or SU(3) breaking effects might contribute at the order of a few percent in $\Xi\rightarrow \Lambda^0\pi$ and $\Xi^*\rightarrow \Xi\pi$ weak decays. We predict that $\mathcal{B}(\Xi^{-}\rightarrow \Sigma^0\mu^-\bar{\nu}_\mu)=(1.13\pm0.08)\times10^{-6}$, $\mathcal{B}(\Xi^{-}\rightarrow\Lambda^0\mu^-\bar{\nu}_\mu)=(1.58\pm0.04)\times10^{-4}$, $\mathcal{B}(\Omega^-\rightarrow\Xi^0\mu^-\bar{\nu}_\mu)=(3.7\pm1.8)\times10^{-3}$, $\mathcal{B}(\Sigma^-\rightarrow \Sigma^0e^-\bar{\nu}_e)=(1.35\pm0.28)\times10^{-10}$, $\mathcal{B}(\Xi^-\rightarrow \Xi^0e^-\bar{\nu}_e)=(4.2\pm2.4)\times10^{-10}$. We also study $T_{10}\to T_8 P_8$ weak, electromagnetic or strong decays. Some of these decay modes could be observed by the BESIII, LHCb and other experiments in the near future. Due to the very small life times of $\Sigma^0$, $\Xi^{*0,-}$, $\Sigma^{*0,-}$ and $\Delta^{0,-}$, the branching ratios of these baryon weak decays are only at the order of $\mathcal{O}(10^{-20}-10^{-13}$), which are too small to be reached by current experiments. Furthermore, the longitudinal branching ratios of $T_{8A} \to T_{8B} \ell^- \bar{\nu}_\ell~(\ell=\mu,e)$ decays are also given.

Radiatively scotogenic type-II seesaw and a relevant phenomenological analysis

When a small vacuum expectation value of Higgs triplet (\U0001d710∆) in the type-II seesaw model is required to explain neutrino oscillation data, a fine-tuning issue occurs on the mass-dimension lepton-number-violation (LNV) scalar coupling. Using the scotogenic approach, we investigate how a small LNV term is arisen through a radiative correction when an Z2-odd vector-like lepton (X) and an Z2-odd right-handed Majorana lepton (N) are introduced to the type-II seesaw model. Due to the dark matter (DM) direct detection constraints, the available DM candidate is the right-handed Majorana particle, whose mass depends on and is close to the mX parameter. Combing the constraints from the DM measurements, the h → γγ decay, and the oblique T -parameter, it is found that the preferred range of v∆ is approximately in the region of 10−5−10−4 GeV; the mass difference between the doubly and the singly charged Higgs is less than 50 GeV, and the influence on the h → Z γ decay is not significant. Using the constrained parameters, we analyze the decays of each Higgs triplet scalar in detail, including the possible three-body decays when the kinematic condition is allowed. It is found that with the exception of doubly charged Higgs, scalar mixing effects play an important role in the Higgs triplet two-body decays when the scalar masses are near-degenerate. In the non-degenerate mass region, the branching ratios of the Higgs triplet decays are dominated by the three-body decays.

Charged Higgs bosons in the NMSSM under current LHC constraints

Charged Higgs boson is a crucial prediction of new physics beyond the SM. In this work, we perform a comprehensive scan over the parameter space of NMSSM considering various experimental constraints including the direct search limits from the 13 TeV LHC, and consider the scenario that the next-to-lightest CP-even Higgs boson is SM-like. We find that the masses of charged Higgs bosons can be as light as 350 GeV, the lightest CP-even Higgs boson [Formula: see text] is predominantly singlet and can be as light as 48 GeV, and the lightest CP-odd Higgs boson [Formula: see text] is also singlet-dominated and can be as light as 82 GeV. The charged Higgs bosons mainly decay to [Formula: see text] or [Formula: see text], but the branching ratio of the exotic decays [Formula: see text] and [Formula: see text] can maximally reach 20% and 11%, respectively, which can be used to distinguish the NMSSM from MSSM. Such a heavy charged Higgs boson is inaccessible at the 13 TeV LHC with a luminosity of 36.1 fb[Formula: see text] and its detection needs higher energy and/or higher luminosity.

Decay behaviors of possible Λcc¯ states in hadronic molecule pictures

In 2010, $\Lambda^*_{c\bar{c}}$ states were predicted as the strange number $S=-1$ partners of $N^*_{c\bar{c}}$, which are well known now as the $P_c$ states and observed experimentally by LHCb Collaboration. We analyze the decay behaviors of $\Lambda_{c\bar{c}}$ as S-wave hadronic molecules within the effective Lagrangian framework by a similar method, which has been applied on $P_c$ states successfully. With partial widths of possible decay channels calculated, we find that $\Lambda_{c\bar{c}}(4213)$ and $\Lambda_{c\bar{c}}(4403)$, which are formed as pseudoscalar meson baryon molecules, mainly decay to the $\eta_c \Lambda$ channel. For the two vector meson baryon molecule states, our results show that the total decay width with $J^P=\frac12^-$ is by one order of magnitude larger than that with $J^P=\frac32^-$. The decay patterns and relative decay ratios are very different for $\Lambda_{c\bar{c}}(4370)$ being a $D_s^{* -} \Lambda_c^+$ or $\bar{D}^{*} \Xi_c$ molecule state. The main decay channels of $\Lambda_{c\bar{c}}(4550)$ are $\bar{D}^{(*)} \Xi^{(*,\prime)}_c$ because of the pseudoscalar meson exchange mechanism. In addition, $\bar{D}^{*} \Xi_c$ is the dominant decay channel of $\Lambda_{c\bar{c}}(4490)$ which is assumed as a $\bar{D} \Xi_c^{*}$ bound state. These decay patterns of the $\Lambda^*_{c\bar{c}}$ states would provide a guidance for their future experimental searches and help us to understand their internal structures.

New narrow nucleon resonances $N^{\ast}(1685)$ and $N^{\ast}(1726)$ within the chiral quark–soliton model

AbstractWe investigate the strong and radiative decay widths of the narrow nucleon resonances $N^*(1685)$ and $N^{\ast}(1726)$ within the framework of the SU(3) chiral quark–soliton model. All the relevant parameters are taken from those used to describe the properties of the baryon octet and decuplet in previous works. The masses of the antidecuplet nucleon and the eikosiheptaplet (27-plet) nucleon with spin 3/2 are determined respectively to be $(1690.2\pm 10.5)\, \mathrm{MeV}$ and $(1719.6\pm7.4)\,\mathrm{MeV}$. The decay width for $N^{\ast}(1685)\to \eta + N$ is found to be approximately three times larger than that for $N^{\ast}(1685)\to \pi + N$. The width of the decay $N^{\ast}\left(1726\right)3/2^+\to \eta + N$ is about 31 times larger than that of $N^{\ast}\left(1726\right)3/2^+\to \pi + N$. The ratio of the radiative decays for $N^*(1685)$ is obtained to be $\Gamma_{nn^*(1685)}/\Gamma_{pp^*(1685)}=8.62\pm3.45$, which explains very well the neutron anomaly. In contrast, we find $\Gamma_{pp^*(1726)}/\Gamma_{nn^*(1726)}=3.72\pm0.64$, which indicates that the production of $N^*(1726)$ is more likely to be observed in the proton channel. We also examine the decay modes of these narrow nucleon resonances with the strangeness hadrons involved.

Direct + Semidirect E1 Photoneutron Reactions: Semimicroscopic Description

The particle-hole dispersive optical model is implemented to describe together E1 photo-absorption and direct + semidirect photoneutron reactions accompanied by excitation of the giant dipole resonance. Being based on this description, a quantitative estimation of the partial and total branching ratios for direct one-neutron decay of the mentioned giant resonance in a few medium-heavy neutron-closed-shell nuclei is obtained. Calculation results are compared with corresponding experimental data.

Assessing internal soundness of hardwood logs through acoustic impact test and waveform analysis

The objective of this study was to explore the potential of an acoustic impact test as a nondestructive evaluation procedure to assess the soundness of hardwood logs in terms of internal decay, void, and defect ratio. Fifteen logs of four hardwood species (black cherry, white oak, red oak, and cottonwood) were obtained and subjected to acoustic impact testing. The logs were subsequently dissected for visual examination and physical mapping of the internal defects. The acoustic response signals were analyzed to derive acoustic velocity (through FFT), time centroid (through moment analysis), and the first- and second-order damping ratio (through continuous wavelet transform). The longitudinal acoustic velocity was found to have a negative, nonlinear relationship with defect ratio (R2 = 0.72), but it lacked sensitivity to small defects and was affected by species. Time centroid proved to be a better predictor than acoustic velocity with an improved correlation with log defect ratio (R2 = 0.87). Wavelet-based damping ratio was found to have a close linear relationship with log defect ratio. Comparing with the first-order damping ratio, the second-order damping ratio had a better predicting power (R2 = 0.92) and was not affected by type and location of defects. The results further indicated that a combination of acoustic velocity, time centroid, and the first- and second-order damping ratios could yield the optimal prediction of log defect ratio. However, considering the sensitivity and simplicity of the waveform analysis, the second-order damping ratio of the response signals could be the best single predicting parameter for assessing the internal soundness of hardwood logs.

Optimal decay ratio of damped slowly rotating Timoshenko beams

AbstractA stability analysis was performed in the problem of a rotating Timoshenko beam whose movement is controlled by the angular acceleration of the driving motor into which the beam is rigidly clamped. We introduce a damping operator with respect to a rotation angle of a cross section area of rotating Timoshenko beam model, and show the asymptotic stability of the system under certain assumptions. We find the optimal damping coefficient, maximizing the stability margin of the system.

Rare top decays as probes of flavorful Higgs bosons

We study a version of Two Higgs Doublet Models with non-standard flavor violation in the up quark sector. We find branching ratios for the rare top decays $t\to hc$ and $t\to hu$ that are within reach of current and future colliders, while other flavor constraints from rare $B$ decays and neutral $D$ meson mixing, as well as constraints from Higgs signal strength measurements remain under control. The most prominent collider signature of the considered setup is $pp \to t H \to tt \bar c$, providing continued motivation to search for same-sign tops at the LHC as well as a simple framework to interpret these searches. As a byproduct of our study, we provide updated SM predictions for the rare top decays BR$(t \to h c)_\text{SM} = (4.19^{+1.08}_{-0.80} \pm 0.16) \times 10^{-15}$ and BR$(t \to h u)_\text{SM} = (3.66^{+0.94}_{-0.70} \pm 0.67) \times 10^{-17}$ with the main uncertainties coming from higher order QCD and CKM matrix elements.