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1.
The lighter chargino three body decays_1~±→_1~0ff' via the W boson and the charged Higgs boson H± were studied in the R-parity conserved Minimal Supersymmetric Standard Model(MSSM).We treat _1~± decays as production and decay of W± and H±:i.e.,_1~±→_1~0W±(H±)→_1~0ff'.Both higgsinolike and wino-like~v1decays were well investigated.These decays are calculated at 1-loop level and the loop corrections are found to be less than three percent.The signal of the charged Higgs H production from~v1decays is discussed.It will offer important information about the chargino and neutralino sector,as well as the charged Higgs sector in the MSSM.  相似文献   

2.
The properties of 125 GeV new particle, which was discovered in 2012 at the Large Hadron Collider (LHC), are found to be consistent with those of the Higgs boson in the standard model (SM). Hereafter the new particle is dubbed as SM-like Higgs boson. However there is still spacious room for physics beyond the SM (BSM) due to the limited energy and luminosity of the LHC. With more data, experiments will scrutinize whether the new particle is indeed the SM one or not. At the same time, one believes that discovery of the SM-like Higgs boson is just the start of the new era of particle physics. The predominant topic is whether there are other new Higgs bosons as speculated in various BSM models. In this short review, we will describe the current status of Higgs physics at the LHC and several BSM models which contain more Higgs sectors. In literatures, there are numerous studies on extended Higgs sector and a comprehensive review is beyond the scope of this review. Instead, we will present two latest studies on Higgs physics: (1) how to detect the charged Higgs boson and measure tan β after including the top polarization information, and (2) how to discover the extra neutral Higgs boson via the pair production of SM-like Higgs boson.  相似文献   

3.
Nutrients transported from catchments are one of the most important sources for lake eutrophication. In this study, the Honghu Lake Basin, located at the middle reaches of the Yangtze River, was chosen as the study area, and the watershed hydrological distribution model SWAT (Soil Water Assessment Tool) was applied to evaluate the trajectory of watershed nutrient transportation over time. Based on the analysis of driving factors, three experiments corresponding to natural, traditional and modern agriculture processes respectively were designed to evaluate the changes of nutrient inputs from catchments under the three environments. The simulation results showed that there were variations in nutrient production and changes in the range and rate. For three periods of the experiments, TN concentrations have changed as 0.12→0.31→1.15 mg/L, and production as 420→1650→6522 T/a; while TP concentrations changed as 0.018→0.057→0.117 mg/L, and production as 78→303→665 T/a. The nutrient transportation experienced slowly long-term increases during 1840--1950, then showed a relatively rapid increase during the period of 1950-1980s and the period from 1980 to early 1990s, with increasing rate of 1.4% and 2.4% respectively. And from the later 1990s to now, an obviously increasing trend with 15% increasing rate occurred. The effect from human activities on the watershed nutrient transportation increased rapidly, and had become a dominant factor in changes of the nutrient transportation.  相似文献   

4.
Rare decays in flavor physics often suffer from Helicity suppress and Loop suppress. Helicity flip is a direct consequence of chiral U(3) symmetry breaking and electroweak symmetry breaking. The identical feature is also shared by the mass generation of SM fermions. In this review, we use the Minimal Supersymmetric Standard Model (MSSM) as an example to illustrate an explicit connection between bottom Yukawa coupling and rare decay process of b → sγ. We take a symmetry approach to study the common symmetry breaking in supersymmetric correction to bottom quark mass generation and b→sγ. We show that Large Peccei-Quinn symmetry breaking effect and R-symmetry breaking effect required by b →sγ inevitably lead to significant reduction of bottom Yukawa Yb. To compromise the reduction in bb, a new decay is also needed to keep the Higgs total width as the SM value.  相似文献   

5.
The paper shows the comparative analysis between the traditional technology and the advanced technology, as for the main processes of pieces blocking, attaching chest interlining, slitting pocket and setting sleeve. The difference of expenditure of time and the ratio of floating times between the hanger production system and traditional assembly line is analyzed as well as, which illustrates the advantages of the modern technics, advanced equipment and hi-technology. Some suggestions are given to further innovate the production technology of men's jacket.  相似文献   

6.
Based on the data of Landsat-TM in 1986 and 2000 and with the applied indices of landscape pattern, an analysis is carried out on the landscape pattern with its evolution in Yuanmou County of Yunnan Province inside the Jinshajiang Xerothermic valley area and a forecast is given on the changing tendency of the landscape pattern in the county with Markov Chain Model. The result shows that the production landscape like irrigated farmland and construction land in town and country as well as ecological building landscape in boondocks were enlarged during 1986-2000. Also the patch shape was regularized and the patch shape index and dimensionality were degraded. The landscape pattern was tattered and the heterogeneity index and Evenness degree were increased but the dominance degree was degraded. The key elements with lower stability cover grassland, water body and bush land. The future transformation of landscape pattern will centralize in construction land‘‘s occupation in irrigated farmland, non-irrigated farmland and grassland, the transformation of non-irrigated farmland to irrigated farmland, forest and sparse wodland or orchard, construction land‘‘s occupation in grassland and cultivation of it into sloping non-irrigated farmland and forest‘‘s degeneracy to bush land, sparse woodland and grassland. The main measures to improve virtuous development of landscape in the xerothermic valley are suggested.  相似文献   

7.
The basic sets of solutions in class H( or H^*) for the characteristic equation and its adjoint equation with Hilbert kernel are given respectively. Thus the expressions of solutions and its solvable conditions are simplified. On this basis the solutions and the solvable conditions in class H1^* as well as the generalized Noether theorem for the complete equation are obtained.  相似文献   

8.
Guizhou Province, located in the southwestern China, is an important mercury (Hg) production center. High levels of Hg were found in local environmental and biomass samples. The neurobiological disruptions induced in brains of rats fed with Hg polluted rice collected from two experimental plots in Guizhou Province were studied. The plots are close to the Hg mine of Wanshang area and a chemical plant (where Hg is used as a catalyst for the production of acetaldehyde) of Qingzhen area. Rats were fed for 30 d before toxicological end points were tested. The results showed that the accumulations of Hg in rat's brain of Qingzhen chemical plant group and Wanshang mine group were significantly higher than those of Shanghai group (control group) (P〈0.01). The neural transmitters, including acetylcholine (Ach), acetylcholine enzyme (AchE), nitric oxide and nitricoxide synthase (NOS), in rat's brain were significantly affected. Oxidative stress was observed in the exposure groups. The expression levels of the immediately early gene (lEG), c-fos and c-FOS proteins were induced by the Hg polluted rice. It was noted that the lEG (c-fos) participated in the neurotoxic process induced by the Hg polluted rice. lEG response to Hg might be dependent on interactions between neural transmitter and oxidative damage, c.fos could be used as an effective index of detecting and assessing the neurotoxicity of Hg. The results suggested that it should be alert to mental health problem in human beings eating Hg-polluted food. More efforts are necessary to protect the local ecosystem and human health in the Hg polluted areas such as Wangshan and Qingzhen in Guizhou Province of China.  相似文献   

9.
Early Yanshanian (Jurassic) granitoids are widespread in the Nanling Range of South China, and are associated with numerous non-ferrous and rare metal mineral deposits. These granitoids consist mainly of slightly peraluminous biotite monzogranites and K-feldspar granites that are closely associated in time and space with subordinate amphibole-bearing granites and muscoviteand garnet-bearing granites. In most previous studies, the biotite-bearing granites were classified as crustal transformation-type (corresponding to the S-type) granites which were interpreted to be derived from the regional Paleoproterozoic meta-sedimentary rocks. In this paper, we re-analyze the geochemical characteristics of a number of representative Early Yanshanian Nanling granitoids. There exists a clear negative correlation between SiO2 and P2O5 for the studied granitoids. The Early Yanshanian Nanling granitoid suites (including amphibole-bearing granodiorites→biotite monzogranites→K-feldspar granites→two-mica (muscovite) granites) are metaluminous to slightly peraluminous I-type or fractionated I-type granites. They were derived predominantly from Proterozoic igneous protoliths. The juvenile crust and/or newly mantle-derived materials might also have been involved in some of these granites. In addition, the Iand fractionated I-type granites are closely associated in time and space with minor amount of A-type felsic and mafic volcanic and intrusive rocks as well as alkaline rocks. All these rocks constitute a typical assemblage of anorogenic, intraplate magmatism, suggesting a dominant lithospheric extensional regime for the Nanling Range and neighboring region during the Early Yanshanian period.  相似文献   

10.
1 Results The effects of different operating parameters on micro proton exchange membrane (PEM) fuel cell performance were experimentally studied for three different flow field configurations (interdigitated,mesh,and serpentine).Experiments with different cell operating temperatures and different backpressures on the H2 flow channels,as well as various combinations of these parameters,have been conducted for three different flow geometries.The micro PEM fuel cells were designed and fabricated in-house through a deep UV lithography technique and the SU-8 photoresist was used as microstructure material for the fuel cell flow field plates.Results are presented in the form of polarization VI curves and PI curves under different operating conditions.The possible transport mechanisms associated with the parametric effects were discussed.Moreover,it was found that among the three flow patterns considered,significant improvements can be reached with a specified flow geometry.  相似文献   

11.
X-ray diffraction (XRD) was employed to analyze the texture evolution of commercial pure (CP) Ti during cold rolling and recrystallization annealing. The texture components were measured by electron backscattered diffraction (EBSD) after recrystallization annealing. The CP Ti tends to form a texture with the basal pole tilted 30°-40° away from the normal direction toward the transverse direction. The texture of the initial hot-rolled plate can be classified into three kinds, i.e., the pyramid texture (1013)[5230] and (2021)[1015], the basal plane texture (0001)[2110], and the stronger prism texture (1120)[0001]. After cold rolling and annealing (700℃, 60 min), the main texture components are the cold-rolled texture (1125)[1123] and the recrystallized texture (1013)[5230]. The texture (2021)[1015] is inherited from the texture of the initial hot-rolled plate with the decrease of orientation density gradually. The volume contents of the cold-rolled texture {2115} <0110> and the recrystallized texture {1013} <1210> are calculated by EBSD. After recrystallization annealing, the specimen is rich in the recrystallized texture and inherits some of texture components from the cold-rolled texture. When the annealing time is prolonged, the anisotropic value decreases.  相似文献   

12.
The total column-averaged volume mixing ratio of atmospheric carbon dioxide (Xco2) has been retrieved with high spectral resolution solar absorption data obtained from ground-based Fourier transform spectrometer (FTS) measurements at Xichong, a coastal site in the district of Shenzhen in southern China. Based on differential optical absorption spectroscopy (DOAS) theory, the Xco2 was retrieved by finding the best match of observed high spectral resolution solar absorption data and monochromatic radia- tion transfer model calculations. The averaged Xco2 in the whole observation period was about 394.9 ppm. The uncertainty of the retrieval was estimated to be 2.0 ppm (0.51%) by comparing retrievals at two bands. The preliminary results show that Xc% retrieved by this method can be used to validate satellite remote sensing of Xco2.  相似文献   

13.
In this short review, we present the current status about the theoretical and experimental studies for some important semileptonic decays of \(B/B_s\) mesons. We firstly gave a brief introduction for the experimental measurements for \(B/B_s \rightarrow P (l^+l^-, l^-\bar{\nu }_l, \nu \bar{\nu })\) decays, the BaBar’s \(R(D)\) and \(R(D^*)\) anomaly, the \(P_5^\prime \) deviation for \(B^0 \rightarrow K^{*0} \mu ^+ \mu ^-\) decay. We then made a careful discussion about the evaluations for the relevant form factors in the light-cone QCD sum rule, the heavy quark effective theory, and the perturbative QCD factorization approach. By using the form factors calculated in the perturbative (pQCD) approach, we then calculate and show the pQCD predictions for the decay rates of many semileptonic decays of \(B/B_s\) mesons. We also made careful phenomenological analysis for these pQCD predictions and found, in general, the following points: (a) For all the considered \(B/B_s\) semileptonic decays, the next-to-leading order pQCD predictions for their decay rates agree well with the data and those from other different theoretical methods; (b) For \(R(D)\) and \(R(D^*)\) , the pQCD predictions agree very well with the data, the BaBar’s anomaly of \(R(D^{(*)})\) are therefore explained successfully in the standard model by employing the pQCD approach; and (c) We defined several new ratios \(R_D^{l,\tau }\) and \(R_{D_s}^{l,\tau }\) , they may be more sensitive to the QCD dynamics which controls the \(B/B_s \rightarrow (D^{(*)},D_s^{(*)} )\) transitions than the old ratios, we therefore strongly suggest LHCb and the forthcoming Super- \(B\) experiments to measure these new ratios.  相似文献   

14.
15.
A graph G is super-edge-connected,for short super-λ,if every minimum edge-cut consists of edges adjacent to a vertex of minimum degree.Alphabet overlap graph G(k,d,s)is undirected,simple graph with vertex set V={v|v=1()kv…v;vi∈{1,2,…,d},i=1,…,k}.Two vertices u=(u1…uk)and v=(v1…vk)are adjacent if and only if us+i=vi or vs+i=ui(i=1,…,k-s).In particular G(k,d,1)is just an undirected de Bruijn graph.In this paper,we show that the diameter of G(k,d,s)is k s,the girth is 3.Finally,we prove that G(k,d,s)(s≥k/2)is super-λ.  相似文献   

16.
Rare decays in flavor physics often suffer from Helicity suppress and Loop suppress. Helicity flip is a direct consequence of chiral \(U(3)\) symmetry breaking and electroweak symmetry breaking. The identical feature is also shared by the mass generation of SM fermions. In this review, we use the Minimal Supersymmetric Standard Model (MSSM) as an example to illustrate an explicit connection between bottom Yukawa coupling and rare decay process of \(b\rightarrow s\gamma \) . We take a symmetry approach to study the common symmetry breaking in supersymmetric correction to bottom quark mass generation and \(b\rightarrow s\gamma \) . We show that Large Peccei-Quinn symmetry breaking effect and \(R\) -symmetry breaking effect required by \(b\rightarrow s\gamma \) inevitably lead to significant reduction of bottom Yukawa \({y}_{b}\) . To compromise the reduction in \(b\bar{b}\) , a new decay is also needed to keep the Higgs total width as the SM value.  相似文献   

17.
The nonleptonic two body \(B_{u,d,s,c}\) decays involving a light tensor meson in final states are studied in the perturbative QCD approach based on \(k_{\mathrm{T}}\) factorization. The decay modes with a tensor meson emitted, are prohibited in naive factorization, since the emission diagram with a tensor meson produced from vacuum is vanished. While contributions from the so-called hard scattering emission diagrams and annihilation type diagrams are important and calculable in the perturbative QCD approach. The branching ratios of most decays are in the range of \(10^{-4}\) \(10^{-8}\) , which are bigger by 1 or 2 orders of magnitude than the predictions given by the naive factorization, but consistent with the predictions from the QCD factorization and the recent experimental measurements. We also give the predictions for the direct \(CP\) asymmetries, some of which are large enough for the future experiments to measure. We also find that, even with a small mixing angle, the mixing between \(f_2\) and \(f_2^{\prime }\) can bring remarkable changes to both branching ratios and the direct \(CP\) asymmetries for some decays involving \(f_2^{(\prime )}\) mesons. For decays with a vector meson and a tensor meson in final states, we predict a large percentage of transverse polarization contributions due to the contributions of the orbital angular momentum of the tensor mesons.  相似文献   

18.
Zuo-Hong Li 《科学通报(英文版)》2014,59(29-30):3771-3786
We report some applications of QCD light cone sum rules (LCSR) to \(B\) meson weak decays. Special emphasis is on estimates of the form factors for \(B\) decays into a pseudoscalar ( \(P\) )/vector ( \(V\) ) meson, with a certain chiral current correlator. The main new ingredient, as compared with the case of the standard correlators, is that in the operator product expansion calculations, the contributions due to the twist-3 distribution amplitudes of the related light mesons, which are less known and would bring a larger uncertainty to the calculations with the standard correlators, cancel out fully in the \(B\rightarrow P\) case and do out partially in the \(B\rightarrow V\) one. An important observation, which is similar to that in soft collinear effective theory, is made in twist-3 approximation: whereas only one independent form factor is needed for parameterizing the hadronic matrix elements for a \(B\rightarrow P\) transition induced by all the relevant heavy-light quark currents, there exist two independent form factors under the condition of neglecting the terms suppressed by a factor of \(m_V^2\) , for the \(B\rightarrow V\) transition. Therefore, the improved LCSR approach could be of stronger predictive power for the weak form factors. Also, this approach is employed to understand the \(B\rightarrow D\) transitions by introducing a leading twist-2 DA for an energetic \(D\) meson, combined with some of other QCD-based approaches. A detailed QCD next-to-leading order calculation of the \(B\rightarrow \pi \) form factors is presented for an illustrative purpose, and the sum rule results are used to extract the Cabibbo–Kobayashi–Maskawa matrix element \(|V_{ub}|\) from the latest BaBar data.  相似文献   

19.
Givenf being Hölder continuous in a regionG?C. For the Cauchy principal integral $$I(\Gamma ,f) = \frac{1}{{\pi i}} \int_\Gamma {\frac{{f(\zeta )}}{{\zeta - \zeta _0 }}d\zeta , \zeta _0 \in \Gamma } $$ where Γ?G is a smooth closed contour, it is established that, if a sequence of smooth closed contours Γn?G(n∈N) smoothly convergent to Γ, then the corresponding sequenceI(Γ n, f)is convergent to I(Γ, f). Furthermore, when Γ is approximated by a sequence of complex cubic splines $S_{\Delta _n } (\Gamma )$ interpolatory to Γ, the error $|I(\Gamma ,f)--I(S_{\Delta _n } (\Gamma ,f)|$ is estimated.  相似文献   

20.
Along with the running of Large Hadron Collider (LHC) located at CERN in November 2009, a large number of data samples of \(B_c\) meson have been collected and some hadronic \(B_c\) decay modes have been measured by the LHC experiments. In view of the special and important roles of \(B_c\) meson decays playing in the heavy flavor sector, we here give a short review on the status of two body hadronic decays \(B_c \rightarrow M_1 M_2\) at both experimental and theoretical aspects. For the theoretical progresses, specifically, we will show lots of theoretical studies on two body hadronic \(B_c\) decays involving pseudoscalar, vector, scalar, axial-vector, even tensor meson(s) in the final states by employing the perturbative QCD (pQCD) factorization approach. We will present a general analysis about the two-body hadronic decays of the heavy \(B_c\) meson and also provide some expectations for the future developments.  相似文献   

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