Probing R-violating top quark decays at the NLC

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The Subleading Isgur-Wise Form Factor $chi_3(vcdot v')$ to Order $alpha_s$ in QCD Sum Rules

a rXiv:h ep-ph/9212266v116Dec1992SLAC–PUB–6017WIS–92/99/Dec–PH December 1992T/E The Subleading Isgur-Wise Form Factor χ3(v ·v ′)to Order αs in QCD Sum Rules Matthias Neubert Stanford Linear Accelerator Center Stanford University,Stanford,California 94309Zoltan Ligeti and Yosef Nir Weizmann Institute of Science Physics Department,Rehovot 76100,Israel We calculate the contributions arising at order αs in the QCD sum rule for the spin-symmetry violating universal function χ3(v ·v ′),which appears at order 1/m Q in the heavy quark expansion of meson form factors.In particular,we derive the two-loop perturbative contribution to the sum rule.Over the kinematic range accessible in B →D (∗)ℓνdecays,we ﬁnd that χ3(v ·v ′)does not exceed the level of ∼1%,indicating that power corrections induced by the chromo-magnetic operator in the heavy quark expansion are small.(submitted to Physical Review D)I.INTRODUCTIONIn the heavy quark eﬀective theory(HQET),the hadronic matrix elements describing the semileptonic decays M(v)→M′(v′)ℓν,where M and M′are pseudoscalar or vector mesons containing a heavy quark,can be systematically expanded in inverse powers of the heavy quark masses[1–5].The coeﬃcients in this expansion are m Q-independent,universal functions of the kinematic variable y=v·v′.These so-called Isgur-Wise form factors characterize the properties of the cloud of light quarks and gluons surrounding the heavy quarks,which act as static color sources.At leading order,a single functionξ(y)suﬃces to parameterize all matrix elements[6].This is expressed in the compact trace formula[5,7] M′(v′)|J(0)|M(v) =−ξ(y)tr{(2)m M P+ −γ5;pseudoscalar meson/ǫ;vector mesonis a spin wave function that describes correctly the transformation properties(under boosts and heavy quark spin rotations)of the meson states in the eﬀective theory.P+=1g s2m Q O mag,O mag=M′(v′)ΓP+iσαβM(v) .(4)The mass parameter¯Λsets the canonical scale for power corrections in HQET.In the m Q→∞limit,it measures theﬁnite mass diﬀerence between a heavy meson and the heavy quark that it contains[11].By factoring out this parameter,χαβ(v,v′)becomes dimensionless.The most general decomposition of this form factor involves two real,scalar functionsχ2(y)andχ3(y)deﬁned by[10]χαβ(v,v′)=(v′αγβ−v′βγα)χ2(y)−2iσαβχ3(y).(5)Irrespective of the structure of the current J ,the form factor χ3(y )appears always in the following combination with ξ(y ):ξ(y )+2Z ¯Λ d M m Q ′ χ3(y ),(6)where d P =3for a pseudoscalar and d V =−1for a vector meson.It thus eﬀectively renormalizes the leading Isgur-Wise function,preserving its normalization at y =1since χ3(1)=0according to Luke’s theorem [10].Eq.(6)shows that knowledge of χ3(y )is needed if one wants to relate processes which are connected by the spin symmetry,such as B →D ℓνand B →D ∗ℓν.Being hadronic form factors,the universal functions in HQET can only be investigated using nonperturbative methods.QCD sum rules have become very popular for this purpose.They have been reformulated in the context of the eﬀective theory and have been applied to the study of meson decay constants and the Isgur-Wise functions both in leading and next-to-leading order in the 1/m Q expansion [12–21].In particular,it has been shown that very simple predictions for the spin-symmetry violating form factors are obtained when terms of order αs are neglected,namely [17]χ2(y )=0,χ3(y )∝ ¯q g s σαβG αβq [1−ξ(y )].(7)In this approach χ3(y )is proportional to the mixed quark-gluon condensate,and it was estimated that χ3(y )∼1%for large recoil (y ∼1.5).In a recent work we have reﬁned the prediction for χ2(y )by including contributions of order αs in the sum rule analysis [20].We found that these are as important as the contribution of the mixed condensate in (7).It is,therefore,worthwhile to include such eﬀects also in the analysis of χ3(y ).This is the purpose of this article.II.DERIV ATION OF THE SUM RULEThe QCD sum rule analysis of the functions χ2(y )and χ3(y )is very similar.We shall,therefore,only brieﬂy sketch the general procedure and refer for details to Refs.[17,20].Our starting point is the correlatord x d x ′d ze i (k ′·x ′−k ·x ) 0|T[¯q ΓM ′P ′+ΓP +iσαβP +ΓM+Ξ3(ω,ω′,y )tr 2σαβ2(1+/v ′),and we omit the velocity labels in h and h ′for simplicity.The heavy-light currents interpolate pseudoscalar or vector mesons,depending on the choice ΓM =−γ5or ΓM =γµ−v µ,respectively.The external momenta k and k ′in (8)are the “residual”oﬀ-shell momenta of the heavy quarks.Due to the phase redeﬁnition of the eﬀective heavy quark ﬁelds in HQET,they are related to the total momenta P and P ′by k =P −m Q v and k ′=P ′−m Q ′v ′[3].The coeﬃcient functions Ξi are analytic in ω=2v ·k and ω′=2v ′·k ′,with discontinuities for positive values of these variables.They can be saturated by intermediate states which couple to the heavy-light currents.In particular,there is a double-pole contribution from the ground-state mesons M and M ′.To leading order in the 1/m Q expansion the pole position is at ω=ω′=2¯Λ.In the case of Ξ2,the residue of the pole is proportional to the universal function χ2(y ).For Ξ3the situation is more complicated,however,since insertions of the chromo-magnetic operator not only renormalize the leading Isgur-Wise function,but also the coupling of the heavy mesons to the interpolating heavy-light currents (i.e.,the meson decay constants)and the physical meson masses,which deﬁne the position of the pole.1The correct expression for the pole contribution to Ξ3is [17]Ξpole 3(ω,ω′,y )=F 2(ω−2¯Λ+iǫ) .(9)Here F is the analog of the meson decay constant in the eﬀective theory (F ∼f M√m QδΛ2+... , 0|j (0)|M (v ) =iF2G 2tr 2σαβΓP +σαβM (v ) ,where the ellipses represent spin-symmetry conserving or higher order power corrections,and j =¯q Γh (v ).In terms of the vector–pseudoscalar mass splitting,the parameter δΛ2isgiven by m 2V −m 2P =−8¯ΛδΛ2.For not too small,negative values of ωand ω′,the coeﬃcient function Ξ3can be approx-imated as a perturbative series in αs ,supplemented by the leading power corrections in 1/ωand 1/ω′,which are proportional to vacuum expectation values of local quark-gluon opera-tors,the so-called condensates [22].This is how nonperturbative corrections are incorporated in this approach.The idea of QCD sum rules is to match this theoretical representation of Ξ3to the phenomenological pole contribution given in (9).To this end,one ﬁrst writes the theoretical expression in terms of a double dispersion integral,Ξth 3(ω,ω′,y )= d νd ν′ρth 3(ν,ν′,y )1Thereare no such additional terms for Ξ2because of the peculiar trace structure associated with this coeﬃcient function.possible subtraction terms.Because of theﬂavor symmetry it is natural to set the Borel parameters associated withωandω′equal:τ=τ′=2T.One then introduces new variables ω±=12T ξ(y) F2e−2¯Λ/T=ω0dω+e−ω+/T ρth3(ω+,y)≡K(T,ω0,y).(12)The eﬀective spectral density ρth3arises after integration of the double spectral density over ω−.Note that for each contribution to it the dependence onω+is known on dimensionalgrounds.It thus suﬃces to calculate directly the Borel transform of the individual con-tributions toΞth3,corresponding to the limitω0→∞in(12).Theω0-dependence can be recovered at the end of the calculation.When terms of orderαs are neglected,contributions to the sum rule forΞ3can only be proportional to condensates involving the gluonﬁeld,since there is no way to contract the gluon contained in O mag.The leading power correction of this type is represented by the diagram shown in Fig.1(d).It is proportional to the mixed quark-gluon condensate and,as shown in Ref.[17],leads to(7).Here we are interested in the additional contributions arising at orderαs.They are shown in Fig.1(a)-(c).Besides a two-loop perturbative contribution, one encounters further nonperturbative corrections proportional to the quark and the gluon condensate.Let usﬁrst present the result for the nonperturbative power corrections.WeﬁndK cond(T,ω0,y)=αs ¯q q TT + αs GG y+1− ¯q g sσαβGαβq√y2−1),δn(x)=1(4π)D×1dλλ1−D∞λd u1∞1/λd u2(u1u2−1)D/2−2where C F=(N2c−1)/2N c,and D is the dimension of space-time.For D=4,the integrand diverges asλ→0.To regulate the integral,we assume D<2and use a triple integration by parts inλto obtain an expression which can be analytically continued to the vicinity of D=4.Next we set D=4+2ǫ,expand inǫ,write the result as an integral overω+,and introduce back the continuum threshold.This givesK pert(T,ω0,y)=−αsy+1 2ω0dω+ω3+e−ω+/T(16)× 12−23∂µ+3αs9π¯Λ,(17)which shows that divergences arise at orderαs.At this order,the renormalization of the sum rule is thus accomplished by a renormalization of the“bare”parameter G2in(12).In the9π¯Λ 1µ2 +O(g3s).(18)Hence a counterterm proportional to¯Λξ(y)has to be added to the bracket on the left-hand side of the sum rule(12).To evaluate its eﬀect on the right-hand side,we note that in D dimensions[17]¯Λξ(y)F2e−2¯Λ/T=3y+1 2ω0dω+ω3+e−ω+/T(19)× 1+ǫ γE−ln4π+2lnω+−ln y+12T ξ(y) F2e−2¯Λ/T=αsy+1 2ω0dω+ω3+e−ω+/T 2lnµ6+ y r(y)−1+ln y+1According to Luke’stheorem,theuniversalfunction χ3(y )vanishes at zero recoil [10].Evaluating (20)for y =1,we thus obtain a sum rule for G 2(µ)and δΛ2.It reads G 2(µ)−¯ΛδΛ224π3ω00d ω+ω3+e −ω+/T ln µ12 +K cond (T,ω0,1),(21)where we have used that r (1)=1.Precisely this sum rule has been derived previously,starting from a two-current correlator,in Ref.[16].This provides a nontrivial check of our ing the fact that ξ(y )=[2/(y +1)]2+O (g s )according to (19),we ﬁnd that the µ-dependent terms cancel out when we eliminate G 2(µ)and δΛ2from the sum rule for χ3(y ).Before we present our ﬁnal result,there is one more eﬀect which has to be taken into account,namely a spin-symmetry violating correction to the continuum threshold ω0.Since the chromo-magnetic interaction changes the masses of the ground-state mesons [cf.(10)],it also changes the masses of higher resonance states.Expanding the physical threshold asωphys =ω0 1+d M8π3 22 δ3 ω032π2ω30e −ω0/T 26π2−r (y )−ξ(y ) δ0 ω096π 248T 1−ξ(y ).It explicitly exhibits the fact that χ3(1)=0.III.NUMERICAL ANALYSISLet us now turn to the evaluation of the sum rule (23).For the QCD parameters we take the standard values¯q q =−(0.23GeV)3,αs GG =0.04GeV4,¯q g sσαβGαβq =m20 ¯q q ,m20=0.8GeV2.(24) Furthermore,we useδω2=−0.1GeV from above,andαs/π=0.1corresponding to the scale µ=2¯Λ≃1GeV,which is appropriate for evaluating radiative corrections in the eﬀective theory[15].The sensitivity of our results to changes in these parameters will be discussed below.The dependence of the left-hand side of(23)on¯Λand F can be eliminated by using a QCD sum rule for these parameters,too.It reads[16]¯ΛF2e−2¯Λ/T=9T4T − ¯q g sσαβGαβq4π2 2T − ¯q q +(2y+1)4T2.(26) Combining(23),(25)and(26),we obtainχ3(y)as a function ofω0and T.These parameters can be determined from the analysis of a QCD sum rule for the correlator of two heavy-light currents in the eﬀective theory[16,18].Oneﬁnds good stability forω0=2.0±0.3GeV,and the consistency of the theoretical calculation requires that the Borel parameter be in the range0.6<T<1.0GeV.It supports the self-consistency of the approach that,as shown in Fig.2,weﬁnd stability of the sum rule(23)in the same region of parameter space.Note that it is in fact theδω2-term that stabilizes the sum rule.Without it there were no plateau.Over the kinematic range accessible in semileptonic B→D(∗)ℓνdecays,we show in Fig.3(a)the range of predictions forχ3(y)obtained for1.7<ω0<2.3GeV and0.7<T< 1.2GeV.From this we estimate a relative uncertainty of∼±25%,which is mainly due to the uncertainty in the continuum threshold.It is apparent that the form factor is small,not exceeding the level of1%.2Finally,we show in Fig.3(b)the contributions of the individual terms in the sum rule (23).Due to the large negative contribution proportional to the quark condensate,the terms of orderαs,which we have calculated in this paper,cancel each other to a large extent.As a consequence,ourﬁnal result forχ3(y)is not very diﬀerent from that obtained neglecting these terms[17].This is,however,an accident.For instance,the order-αs corrections would enhance the sum rule prediction by a factor of two if the ¯q q -term had the opposite sign. From thisﬁgure one can also deduce how changes in the values of the vacuum condensates would aﬀect the numerical results.As long as one stays within the standard limits,the sensitivity to such changes is in fact rather small.For instance,working with the larger value ¯q q =−(0.26GeV)3,or varying m20between0.6and1.0GeV2,changesχ3(y)by no more than±0.15%.In conclusion,we have presented the complete order-αs QCD sum rule analysis of the subleading Isgur-Wise functionχ3(y),including in particular the two-loop perturbative con-tribution.Weﬁnd that over the kinematic region accessible in semileptonic B decays this form factor is small,typically of the order of1%.When combined with our previous analysis [20],which predicted similarly small values for the universal functionχ2(y),these results strongly indicate that power corrections in the heavy quark expansion which are induced by the chromo-magnetic interaction between the gluonﬁeld and the heavy quark spin are small.ACKNOWLEDGMENTSIt is a pleasure to thank Michael Peskin for helpful discussions.M.N.gratefully acknowl-edgesﬁnancial support from the BASF Aktiengesellschaft and from the German National Scholarship Foundation.Y.N.is an incumbent of the Ruth E.Recu Career Development chair,and is supported in part by the Israel Commission for Basic Research and by the Minerva Foundation.This work was also supported by the Department of Energy,contract DE-AC03-76SF00515.REFERENCES[1]E.Eichten and B.Hill,Phys.Lett.B234,511(1990);243,427(1990).[2]B.Grinstein,Nucl.Phys.B339,253(1990).[3]H.Georgi,Phys.Lett.B240,447(1990).[4]T.Mannel,W.Roberts and Z.Ryzak,Nucl.Phys.B368,204(1992).[5]A.F.Falk,H.Georgi,B.Grinstein,and M.B.Wise,Nucl.Phys.B343,1(1990).[6]N.Isgur and M.B.Wise,Phys.Lett.B232,113(1989);237,527(1990).[7]J.D.Bjorken,Proceedings of the18th SLAC Summer Institute on Particle Physics,pp.167,Stanford,California,July1990,edited by J.F.Hawthorne(SLAC,Stanford,1991).[8]M.B.Voloshin and M.A.Shifman,Yad.Fiz.45,463(1987)[Sov.J.Nucl.Phys.45,292(1987)];47,801(1988)[47,511(1988)].[9]A.F.Falk,B.Grinstein,and M.E.Luke,Nucl.Phys.B357,185(1991).[10]M.E.Luke,Phys.Lett.B252,447(1990).[11]A.F.Falk,M.Neubert,and M.E.Luke,SLAC preprint SLAC–PUB–5771(1992),toappear in Nucl.Phys.B.[12]M.Neubert,V.Rieckert,B.Stech,and Q.P.Xu,in Heavy Flavours,edited by A.J.Buras and M.Lindner,Advanced Series on Directions in High Energy Physics(World Scientiﬁc,Singapore,1992).[13]A.V.Radyushkin,Phys.Lett.B271,218(1991).[14]D.J.Broadhurst and A.G.Grozin,Phys.Lett.B274,421(1992).[15]M.Neubert,Phys.Rev.D45,2451(1992).[16]M.Neubert,Phys.Rev.D46,1076(1992).[17]M.Neubert,Phys.Rev.D46,3914(1992).[18]E.Bagan,P.Ball,V.M.Braun,and H.G.Dosch,Phys.Lett.B278,457(1992);E.Bagan,P.Ball,and P.Gosdzinsky,Heidelberg preprint HD–THEP–92–40(1992).[19]B.Blok and M.Shifman,Santa Barbara preprint NSF–ITP–92–100(1992).[20]M.Neubert,Z.Ligeti,and Y.Nir,SLAC preprint SLAC–PUB–5915(1992).[21]M.Neubert,SLAC preprint SLAC–PUB–5992(1992).[22]M.A.Shifman,A.I.Vainshtein,and V.I.Zakharov,Nucl.Phys.B147,385(1979);B147,448(1979).FIGURESFIG.1.Diagrams contributing to the sum rule for the universal form factorχ3(v·v′):two-loop perturbative contribution(a),and nonperturbative contributions proportional to the quark con-densate(b),the gluon condensate(c),and the mixed condensate(d).Heavy quark propagators are drawn as double lines.The square represents the chromo-magnetic operator.FIG.2.Analysis of the stability region for the sum rule(23):The form factorχ3(y)is shown for y=1.5as a function of the Borel parameter.From top to bottom,the solid curves refer toω0=1.7,2.0,and2.3GeV.The dashes lines are obtained by neglecting the contribution proportional toδω2.FIG.3.(a)Prediction for the form factorχ3(v·v′)in the stability region1.7<ω0<2.3 GeV and0.7<T<1.2GeV.(b)Individual contributions toχ3(v·v′)for T=0.8GeV and ω0=2.0GeV:total(solid),mixed condensate(dashed-dotted),gluon condensate(wide dots), quark condensate(dashes).The perturbative contribution and theδω2-term are indistinguishable in thisﬁgure and are both represented by the narrow dots.11。

深度优先局部聚合哈希

Vol.48，No.6Jun. 202 1第48卷第6期2 0 2 1年6月湖南大学学报)自然科学版)Journal of Hunan University (Natural Sciences )文章编号：1674-2974(2021 )06-0058-09 DOI ： 10.16339/ki.hdxbzkb.2021.06.009深度优先局艺B 聚合哈希龙显忠g,程成李云12(1.南京邮电大学计算机学院，江苏南京210023；2.江苏省大数据安全与智能处理重点实验室，江苏南京210023)摘要：已有的深度监督哈希方法不能有效地利用提取到的卷积特征，同时，也忽视了数据对之间相似性信息分布对于哈希网络的作用，最终导致学到的哈希编码之间的区分性不足.为了解决该问题，提出了一种新颖的深度监督哈希方法，称之为深度优先局部聚合哈希(DeepPriority Local Aggregated Hashing , DPLAH ). DPLAH 将局部聚合描述子向量嵌入到哈希网络中，提高网络对同类数据的表达能力，并且通过在数据对之间施加不同权重，从而减少相似性信息分布倾斜对哈希网络的影响.利用Pytorch 深度框架进行DPLAH 实验，使用NetVLAD 层对Resnet18网络模型输出的卷积特征进行聚合，将聚合得到的特征进行哈希编码学习.在CI-FAR-10和NUS-WIDE 数据集上的图像检索实验表明，与使用手工特征和卷积神经网络特征的非深度哈希学习算法的最好结果相比,DPLAH 的平均准确率均值要高出11%，同时，DPLAH 的平均准确率均值比非对称深度监督哈希方法高出2%.关键词：深度哈希学习；卷积神经网络；图像检索；局部聚合描述子向量中图分类号:TP391.4文献标志码:ADeep Priority Local Aggregated HashingLONG Xianzhong 1，覮，CHENG Cheng1,2,LI Yun 1,2(1. School of Computer Science & Technology ,Nanjing University of Posts and Telecommunications ,Nanjing 210023, China ;2. Key Laboratory of Jiangsu Big Data Security and Intelligent Processing ,Nanjing 210023, China )Abstract : The existing deep supervised hashing methods cannot effectively utilize the extracted convolution fea tures, but also ignore the role of the similarity information distribution between data pairs on the hash network, result ing in insufficient discrimination between the learned hash codes. In order to solve this problem, a novel deep super vised hashing method called deep priority locally aggregated hashing (DPLAH) is proposed in this paper, which em beds the vector of locally aggregated descriptors (VLAD) into the hash network, so as to improve the ability of the hashnetwork to express the similar data, and reduce the impact of similarity distribution skew on the hash network by im posing different weights on the data pairs. DPLAH experiment is carried out by using the Pytorch deep framework. Theconvolution features of the Resnet18 network model output are aggregated by using the NetVLAD layer, and the hashcoding is learned by using the aggregated features. The image retrieval experiments on the CIFAR-10 and NUS - WIDE datasets show that the mean average precision (MAP) of DPLAH is11 percentage points higher than that of* 收稿日期：2020-04-26基金项目：国家自然科学基金资助项目(61906098,61772284),National Natural Science Foundation of China(61906098, 61772284);国家重点研发计划项目(2018YFB 1003702) , National Key Research and Development Program of China (2018YFB1003702)作者简介:龙显忠(1985—),男，河南信阳人，南京邮电大学讲师，工学博士，硕士生导师覮通信联系人,E-mail ： *************.cn第6期龙显忠等:深度优先局部聚合哈希59non-deep hash learning algorithms using manual features and convolution neural network features,and the MAP of DPLAH is2percentage points higher than that of asymmetric deep supervised hashing method.Key words:deep Hash learning;convolutional neural network;image retrieval;vector of locally aggregated de-scriptors(VLAD)随着信息检索技术的不断发展和完善，如今人们可以利用互联网轻易获取感兴趣的数据内容，然而，信息技术的发展同时导致了数据规模的迅猛增长.面对海量的数据以及超大规模的数据集，利用最近邻搜索［1(Nearest Neighbor Search,NN)的检索技术已经无法获得理想的检索效果与可接受的检索时间.因此,近年来,近似最近邻搜索［2(Approximate Nearest Neighbor Search,ANN)变得越来越流行,它通过搜索可能相似的几个数据而不再局限于返回最相似的数据，在牺牲可接受范围的精度下提高了检索效率.作为一种广泛使用的ANN搜索技术，哈希方法(Hashing)［3］将数据转换为紧凑的二进制编码(哈希编码)表示，同时保证相似的数据对生成相似的二进制编码.利用哈希编码来表示原始数据，显著减少了数据的存储和查询开销，从而可以应对大规模数据中的检索问题.因此，哈希方法吸引了越来越多学者的关注.当前哈希方法主要分为两类：数据独立的哈希方法和数据依赖的哈希方法，这两类哈希方法的区别在于哈希函数是否需要训练数据来定义.局部敏感哈希(Locality Sensitive Hashing,LSH)［4］作为数据独立的哈希代表，它利用独立于训练数据的随机投影作为哈希函数•相反，数据依赖哈希的哈希函数需要通过训练数据学习出来，因此，数据依赖的哈希也被称为哈希学习，数据依赖的哈希通常具有更好的性能.近年来，哈希方法的研究主要侧重于哈希学习方面.根据哈希学习过程中是否使用标签，哈希学习方法可以进一步分为：监督哈希学习和无监督哈希学习.典型的无监督哈希学习包括:谱哈希［5(Spectral Hashing,SH);迭代量化哈希［6］(Iterative Quantization, ITQ);离散图哈希［7(Discrete Graph Hashing,DGH);有序嵌入哈希［8］(Ordinal Embedding Hashing,OEH)等.无监督哈希学习方法仅使用无标签的数据来学习哈希函数，将输入的数据映射为哈希编码的形式.相反,监督哈希学习方法通过利用监督信息来学习哈希函数,由于利用了带有标签的数据,监督哈希方法往往比无监督哈希方法具有更好的准确性，本文的研究主要针对监督哈希学习方法.传统的监督哈希方法包括：核监督哈希［9］(Supervised Hashing with Kernels,KSH);潜在因子哈希［10］(Latent Factor Hashing,LFH);快速监督哈希［11］(Fast Supervised Hashing,FastH);监督离散哈希［1(Super-vised Discrete Hashing,SDH)等.随着深度学习技术的发展［13］,利用神经网络提取的特征已经逐渐替代手工特征，推动了深度监督哈希的进步.具有代表性的深度监督哈希方法包括:卷积神经网络哈希［1(Convolutional Neural Networks Hashing,CNNH);深度语义排序哈希［15］(Deep Semantic Ranking Based Hash-ing,DSRH);深度成对监督哈希［16］(Deep Pairwise-Supervised Hashing,DPSH);深度监督离散哈希［17］(Deep Supervised Discrete Hashing,DSDH);深度优先哈希［18］(Deep Priority Hashing,DPH)等.通过将特征学习和哈希编码学习(或哈希函数学习)集成到一个端到端网络中，深度监督哈希方法可以显著优于非深度监督哈希方法.到目前为止，大多数现有的深度哈希方法都采用对称策略来学习查询数据和数据集的哈希编码以及深度哈希函数.相反，非对称深度监督哈希［19］(Asymmetric Deep Supervised Hashing,ADSH)以非对称的方式处理查询数据和整个数据库数据，解决了对称方式中训练开销较大的问题，仅仅通过查询数据就可以对神经网络进行训练来学习哈希函数，整个数据库的哈希编码可以通过优化直接得到.本文的模型同样利用了ADSH的非对称训练策略.然而，现有的非对称深度监督哈希方法并没有考虑到数据之间的相似性分布对于哈希网络的影响,可能导致结果是:容易在汉明空间中保持相似关系的数据对,往往会被训练得越来越好;相反,那些难以在汉明空间中保持相似关系的数据对，往往在训练后得到的提升并不显著.同时大部分现有的深度监督哈希方法在哈希网络中没有充分有效利用提60湖南大学学报(自然科学版)2021年取到的卷积特征.本文提出了一种新的深度监督哈希方法，称为深度优先局部聚合哈希(Deep Priority Local Aggregated Hashing,DPLAH).DPLAH的贡献主要有三个方面:1)DPLAH采用非对称的方式处理查询数据和数据库数据，同时DPLAH网络会优先学习查询数据和数据库数据之间困难的数据对，从而减轻相似性分布倾斜对哈希网络的影响.2)DPLAH设计了全新的深度哈希网络，具体来说,DPLAH将局部聚合表示融入到哈希网络中，提高了哈希网络对同类数据的表达能力.同时考虑到数据的局部聚合表示对于分类任务的有效性.3)在两个大型数据集上的实验结果表明，DPLAH在实际应用中性能优越.1相关工作本节分别对哈希学习［3］、NetVLAD［20］和Focal Loss［21］进行介绍.DPLAH分别利用NetVLAD和Focal Loss提高哈希网络对同类数据的表达能力及减轻数据之间相似性分布倾斜对于哈希网络的影响. 1.1哈希学习哈希学习［3］的任务是学习查询数据和数据库数据的哈希编码表示，同时要满足原始数据之间的近邻关系与数据哈希编码之间的近邻关系相一致的条件.具体来说，利用机器学习方法将所有数据映射成{0,1}r形式的二进制编码(r表示哈希编码长度)，在原空间中不相似的数据点将被映射成不相似)即汉明距离较大)的两个二进制编码，而原空间中相似的两个数据点将被映射成相似(即汉明距离较小)的两个二进制编码.为了便于计算，大部分哈希方法学习{-1,1}r形式的哈希编码，这是因为{-1,1}r形式的哈希编码对之间的内积等于哈希编码的长度减去汉明距离的两倍，同时{-1,1}r形式的哈希编码可以容易转化为{0,1}r形式的二进制编码.图1是哈希学习的示意图.经过特征提取后的高维向量被用来表示原始图像，哈希函数h将每张图像映射成8bits的哈希编码,使原来相似的数据对(图中老虎1和老虎2)之间的哈希编码汉明距离尽可能小，原来不相似的数据对(图中大象和老虎1)之间的哈希编码汉明距离尽可能大.h（大象）=10001010h（老虎1）=01100001h（老虎2）=01100101相似度尽可能小相似度尽可能大图1哈希学习示意图Fig.1Hashing learning diagram1.2NetVLADNetVLAD的提出是用于解决端到端的场景识别问题［20(场景识别被当作一个实例检索任务),它将传统的局部聚合描述子向量(Vector of Locally Aggregated Descriptors,VLAD［22］)结构嵌入到CNN网络中，得到了一个新的VLAD层.可以容易地将NetVLAD 使用在任意CNN结构中，利用反向传播算法进行优化，它能够有效地提高对同类别图像的表达能力，并提高分类的性能.NetVLAD的编码步骤为：利用卷积神经网络提取图像的卷积特征;利用NetVLAD层对卷积特征进行聚合操作.图2为NetVLAD层的示意图.在特征提取阶段,NetVLAD会在最后一个卷积层上裁剪卷积特征，并将其视为密集的描述符提取器，最后一个卷积层的输出是H伊W伊D映射，可以将其视为在H伊W空间位置提取的一组D维特征,该方法在实例检索和纹理识别任务［23別中都表现出了很好的效果.NetVLAD layer（KxD）x lVLADvectorh------->图2NetVLAD层示意图⑷Fig.2NetVLAD layer diagram1201NetVLAD在特征聚合阶段，利用一个新的池化层对裁剪的CNN特征进行聚合，这个新的池化层被称为NetVLAD层.NetVLAD的聚合操作公式如下：NV((，k)二移a(x)(血⑺-C((j))(1)i=1式中:血(j)和C)(j)分别表示第i个特征的第j维和第k个聚类中心的第j维；恣&)表示特征您与第k个视觉单词之间的权.NetVLAD特征聚合的输入为：NetVLAD裁剪得到的N个D维的卷积特征,K个聚第6期龙显忠等:深度优先局部聚合哈希61类中心.VLAD的特征分配方式是硬分配,即每个特征只和对应的最近邻聚类中心相关联，这种分配方式会造成较大的量化误差，并且，这种分配方式嵌入到卷积神经网络中无法进行反向传播更新参数.因此,NetVLAD采用软分配的方式进行特征分配，软分配对应的公式如下：-琢II Xi-C*II 2=—e(2)-琢II X-Ck，II2k，如果琢寅+肄,那么对于最接近的聚类中心,龟&)的值为1,其他为0.aS)可以进一步重写为：w j X i+b ka(x i)=—e-)3)w J'X i+b kk，式中:W k=2琢C k；b k=-琢||C k||2.最终的NetVLAD的聚合表示可以写为：N w；x+b kv(j，k)=移—----(x(j)-Ck(j))(4)i=1w j.X i+b k移ek，1.3Focal Loss对于目标检测方法,一般可以分为两种类型:单阶段目标检测和两阶段目标检测,通常情况下，两阶段的目标检测效果要优于单阶段的目标检测.Lin等人［21］揭示了前景和背景的极度不平衡导致了单阶段目标检测的效果无法令人满意,具体而言，容易被分类的背景虽然对应的损失很低，但由于图像中背景的比重很大,对于损失依旧有很大的贡献,从而导致收敛到不够好的一个结果.Lin等人［21］提出了Focal Loss应对这一问题，图3是对应的示意图.使用交叉爛作为目标检测中的分类损失，对于易分类的样本,它的损失虽然很低，但数据的不平衡导致大量易分类的损失之和压倒了难分类的样本损失,最终难分类的样本不能在神经网络中得到有效的训练.Focal Loss的本质是一种加权思想，权重可根据分类正确的概率p得到，利用酌可以对该权重的强度进行调整.针对非对称深度哈希方法，希望难以在汉明空间中保持相似关系的数据对优先训练,具体来说,对于DPLAH的整体训练损失，通过施加权重的方式,相对提高难以在汉明空间中保持相似关系的数据对之间的训练损失.然而深度哈希学习并不是一个分类任务,因此无法像Focal Loss一样根据分类正确的概率设计权重，哈希学习的目的是学到保相似性的哈希编码，本文最终利用数据对哈希编码的相似度作为权重的设计依据具体的权重形式将在模型部分详细介绍.正确分类的概率图3Focal Loss示意图［21】Fig.3Focal Loss diagram12112深度优先局部聚合哈希2.1基本定义DPLAH模型采用非对称的网络设计.Q={0},=1表示n张查询图像,X={X i}m1表示数据库有m张图像；查询图像和数据库图像的标签分别用Z={Z i},=1和Y ={川1表示；i=［Z i1，…,zj1,i=1，…,n;c表示类另数；如果查询图像0属于类别j,j=1，…,c;那么z”=1,否则=0.利用标签信息，可以构造图像对的相似性矩阵S沂{-1,1}"伊”,s”=1表示查询图像q,和数据库中的图像X j语义相似,S j=-1表示查询图像和数据库中的图像X j语义不相似.深度哈希方法的目标是学习查询图像和数据库中图像的哈希编码，查询图像的哈希编码用U沂{-1,1}""，表示,数据库中图像的哈希编码用B沂{-1,1}m伊r表示，其中r表示哈希编码的长度.对于DPLAH模型,它在特征提取部分采用预训练好的Resnet18网络［25］.图4为DPLAH网络的结构示意图，利用NetVLAD层聚合Resnet18网络提取到的卷积特征，哈希编码通过VLAD编码得到，由于VLAD编码在分类任务中被广泛使用，于是本文将NetVLAD层的输出作为分类任务的输入，利用图像的标签信息监督NetVLAD层对卷积特征的利用.事实上，任何一种CNN模型都能实现图像特征提取的功能，所以对于选用哪种网络进行特征学习并不是本文的重点.62湖南大学学报(自然科学版)2021年conv1图4DPLAH结构Fig.4DPLAH structure图像标签soft-max1,0,1,1,0□1,0,0,0,11,1,0,1,0---------*----------VLADVLAD core)c)l・>:i>数据库图像的哈希编码2.2DPLAH模型的目标函数为了学习可以保留查询图像与数据库图像之间相似性的哈希编码，一种常见的方法是利用相似性的监督信息S e{-1,1}n伊"、生成的哈希编码长度r,以及查询图像的哈希编码仏和数据库中图像的哈希编码b三者之间的关系[9],即最小化相似性的监督信息与哈希编码对内积之间的L损失.考虑到相似性分布的倾斜问题，本文通过施加权重来调节查询图像和数据库图像之间的损失，其公式可以表示为：min J=移移(1-w)(u T b j-rs)专,B i=1j=1s.t.U沂{-1,1}n伊r,B沂{-1,1}m伊r,W沂R n伊m(5)受FocalLoss启发,希望深度哈希网络优先训练相似性不容易保留图像对，然而Focal Loss利用图像的分类结果对损失进行调整，因此，需要重新进行设计，由于哈希学习的目的是为了保留图像在汉明空间中的相似性关系，本文利用哈希编码的余弦相似度来设计权重,其表达式为：1+。

Autodesk Nastran 2023 参考手册说明书

DATINFILE1 ........................................................................................................................................................... 9
FILESPEC ............................................................................................................................................................ 13
DISPFILE ............................................................................................................................................................. 11
File Management Directives – Output File Specifications: .............................................................................. 5
BULKDATAFILE .................................................................................................................................................... 7

Search for a new state of matter – the Quark-Gluon Plasma一个物质–夸克胶子等离子体的新状态搜索 43

-- Fragmentation
-- multi-parton dynamics (recombination or coalescence or …)
-- Hydrodynamics (constituent quarks ? parton dynamics from gluons to constituent quarks? )
Nucleus-Nucleus Collisions and Volcanic Eruption
Volcanic high pT -- Strombolian eruption
Volcanic mediate pT – Spatter (clumps)
6
Volcanic low pT – Bulk matter flows
Evidence for Multi-parton Dynamics in Hadronization of Bulk Partonic Matter at RHIC
Huan Zhong Huang (黄焕中) Department of Physics and Astronomy
University of California Los Angeles
Rafelski+Danos, Molnar+Voloshin …..) Quark Recombination – (R.J. Fries et al, R. Hwa et al)
13
Constituent Quark Scaling
Constituent (n) Quark Scaling -- Meson n=2 and Baryon n=3 grouping
p td d td p N y d 2 1 π p td dtd p N 1 y i 12ic vo s ψ R () i)1( 0

topsis灰色关联法代码

topsis灰色关联法代码Topsis灰色关联法是一种多属性决策分析方法，它可以用来确定最佳方案。

这种方法将样本的各种特征值进行加权求和，从而得出该样本的综合得分，以此来衡量其在特定领域中的优劣程度。

本文将介绍Topsis灰色关联法的代码实现。

首先，我们需要准备好样本数据。

我们需要将样本的各种特征值以矩阵的形式进行存储。

假设我们有m个样本，n个特征，那么我们可以定义一个m*n的矩阵来存储这些数据。

接下来，我们需要对数据进行标准化处理。

标准化可以使得数据的单位和量纲相同，从而避免因为特征值的不同而导致的误差。

我们可以使用以下代码来进行标准化：```pythonfrom sklearn.preprocessing import StandardScalerscaler = StandardScaler()X = scaler.fit_transform(X)```其中，X是我们准备好的样本数据矩阵。

接着，我们需要为每个特征值进行权重分配。

这个过程可以使用主成分分析（PCA）或者因子分析等方法来完成。

在这里，我们可以使用如下代码来确定特征值的权重：```pythonfrom sklearn.decomposition import PCApca = PCA(n_components=n)pca.fit(X)W = pca.explained_variance_ratio_```其中，n是我们的特征个数。

在这段代码中，我们使用PCA来计算各个特征值的主成分贡献率，并将其作为特征值的权重。

接下来，我们需要对标准化后的样本数据进行灰色关联分析。

这个过程可以使用如下代码来完成：```pythonimport numpy as npdef grey_relation_score(X, w):m, n = X.shapeX0 = np.zeros((m, n))for j in range(n):minx = np.min(X[:, j])maxx = np.max(X[:, j])X0[:, j] = (X[:, j] - minx) / (maxx - minx)S = np.zeros(m)for i in range(m):d = np.abs(X0 - X0[i])s = d.min(axis=1)r = d.max(axis=1)S[i] = (np.sum(s * w) + 0.5 * np.sum(r * w)) / (np.sum(w) + 0.5)return S```在这段代码中，我们首先对标准化后的样本数据进行归一化处理，使得所有数据都在[0,1]之间。

The Sequential Quadratic Programming Method

The Sequential Quadratic Programming Method
167
2 ewton Methods and Local Optimality
In this and subsequent sections we trace the development of Newton methods from the simplest case of nonlinear equations, through to the general case of nonlinear programming with equations and inequalities.
x∈IR
subject to ci (x) ≥ 0
i = 1 , 2 , . . . , m.
(1.1)
In this formulation, equation constraints must be encoded as two opposed inequality constraints, that is c(x) = 0 is replaced by c(x) ≥ 0 and −c(x) ≥ 0, which is usually not convenient. Thus in practice a more detailed formulation is appropriate, admitting also equations, linear constraints and simple bounds. One way to do this is to add slack variables to the constraints, which
The Sequential Quadratic Programming Method

starrocks 存算分离 disable cache参数

starrocks 存算分离disable cache参数StarRocks（星环）的最新版本为 1.19，以下是关于存算分离（Storage-Compute Separation）以及禁用缓存（Disable Cache）的一些建议，注意这些信息可能随着版本的更新而变化，建议查看最新文档或源代码以获取准确的信息。

存算分离（Storage-Compute Separation）：
在StarRocks中，存算分离是一种架构设计，其中存储层（存储引擎）和计算层（计算引擎）分离。

存储引擎负责数据存储和管理，而计算引擎负责执行查询操作。

这种分离可以提高系统的灵活性和可扩展性。

禁用缓存（Disable Cache）：
如果你想禁用查询缓存，通常可以在执行查询时使用相应的查询选项。

在StarRocks中，可能会有一些参数或选项来控制查询缓存的行为。

请查看相关文档或查询引擎的配置选项。

在某些场景下，你可能想要禁用缓存来确保每次查询都是基于最新的数据执行的。

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具体的参数名称和用法可能会根据StarRocks的版本而有所不同。

以下是一些可能的示例：
-- 在查询中禁用缓存
SET disable_cache=1;
SELECT * FROM your_table;
-- 或者在整个会话期间禁用缓存
SET GLOBAL disable_cache=1;
请确保查阅最新的StarRocks文档或相关资源，以获取最准确的信息和配置选项。

withanemphasison

directory – You are ready to go!
MSU NSCL DAQ School—Notre Dame 2006
More to Read
• MSU NSCL DAQ:
– Everything: /daq/index.php
– Software project: /projects/nscldaq
– Tree parameter GUI for powerful manipulation of the definition of parameters, spectra, variables, and gates
– Xamine for easy display and operations of histograms – Tcl/Tk for user-tailorable control GUI and easy extension of
SpectroDaq Data Server
SpecTcl Xamine
Scalers
Scaler Configuration
offline analysis
MSU NSCL DAQ School—Notre Dame 2006
Disk
Hardware Setup
¾ Caen v785, 32-ch ADC ¾ Caen v775, 32-ch TDC ¾ Caen v830, 32-ch Scaler ¾ Trigger to be upgraded
• SpecTcl
– Home: /daq/spectcl/ – Project: /projects/nsclspectcl – Tree Parameters:
/daq/spectcl/treeparam/TreeParameter.html – Tcl/Tk: /

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a r X i v :h e p -p h /0104184v 1 18 A p r 2001AMES-HET-01-06April 2001Probing R -violating top quark decays at the NLC K.J.Abraham a ,Kerry Whisnant a ,Jin Min Yang b ,Bing-Lin Young a a Department of Physics and Astronomy,Iowa State University,Ames,Iowa 50011,USA b Institute of Theoretical Physics,Academia Sinica,Beijing 100080,China ABSTRACT We examine the possibility of observing exotic top quark decays via R -Parity violating SUSY interactions in e +e −collisions at √t via the R -Parity violating interaction while the other undergoes the SM decay.We discuss kinematic cuts that allow the exotic SUSY decays to be detected over standard model backgrounds.Discovery limits for R -Parity violating couplings in the top sector are presented assuming an integrated luminosity of 100fb −1.Even though there is noﬁrm evidence contradicting the Standard Model,it is widely believed to be the low energy approximation of a more fundamental theory.The cur-rently most popular possible extension of the Standard Model is the minimal supersym-metric model(MSSM)which not only can account for all existing precision electroweak mesurements but also predicts a whole host of new particles and decays waiting to be observed.In its simplest form the MSSM has a global symmetry R-parity[1],deﬁned by R=(−1)2S+3B+L with spin S,baryon-number B and lepton-number L which is im-plemented in such a way as to conserve both B and L seperately.However,there is no fundamental requirement for R conservation,indeed it is known that instanton eﬀects induce miniscule violations of both B and L[2].Thus if SUSY is discovered and R-parity turns out to be conserved,it is conceivable that some hitherto unidentiﬁed fundamental principle is at work.Hence R-parity violation should be vigorously searched for.Constraints on the R-parity violating couplings have been obtained from various analyses;however as summarized in Ref.[3],although many such couplings have been severely constrained,existing bounds on the top quark couplings are generally quite weak.This is our motivation for the phenomenological study of R-violation in processes involving the top quark.In what follows,we study the feasibility of detecting B violating R-parity interactions(i.e.λ′′couplings only)in top production and decay in e+e−√collisions attt pairs in a relatively clean environment[4],it is reasonable to expect that either R-parity violating SUSY will be discovered or the parameter space further restricted.Unlike the case of a hadron collider,where B violating couplings lead to newt proceeds via the R-parity Violating interactions;one quark thus decays via Standard Model channels.With the restriction to B-Violating couplings1only,the possible exotic decay modes aret→˜¯d i¯d j,˜¯d j¯d i→¯d i¯d j˜χ01(1) Sfermions involved in these decays can be on-shell or virtual,depending on the masses of the particles involved.All calculations are performed using the narrow width approx-imation with top spin correllations taken fully into acount.Among the decay modes which are relatively easy to detect are those induced byλ′′3j3. Sinceλ′′333vanishes due to the requirement of anti-symmetry on theﬁnal two indices we consider only the cases where i=1,2.To keep the analysis simple we assume that either one,but not both,of the tri-linear coupling just mentioned takes a non-vanishing value. Our analysis can be easily extended to the case where both couplings are non-vanishing in the limit that the down type squarks are approximately degenerate.In our analysis we focus on the case of whereλ′′313is non-vanishing.As shown in Eq.(1),the decay t→¯b¯d˜χ01can proceed through exchange of a sbottom(˜b)or adown squark(˜d).Since among the down-type squarks the sbottom is most likely to be signiﬁcantly lighter than others2,we assume the channel of exchanging a sbottom gives the dominant contribution.Since only a light sbottom is meaningful to our analysis, the dominant decay mode of the sbottom is˜b→b˜χ01.The charged current decay mode ˜b→t˜χ+is kinematically forbidden for a light sbottom in our analysis.We do not 1consider the strong decay mode˜b→b˜g since the gluino˜g is likely to be heavy[8].Note that the LSP(˜χ01)is no longer stable when R-parity is violated.In case just one R-violating top quark coupling does not vanish,the lifetime of the LSP will be very long, depending on the coupling and the masses of squarks involved in the LSP decay chain (cf.the last paper of[3]).We restrict ourselves to the same region of SUSY parameter space as in[9],leading to an LSP which decays outside the detector.In this case,theﬁnal state in the exotic decay of the t ort)decays,we will have a very distinctive signal consisting ofﬁve jets and missing energy.(The inclusion of semi-leptonic standard model decays not only does not increase the signal by much but also complicates the reconstruction of the top pair due to multiple sources of missing energy.)The main standard model backgrounds are:•W+W−Z production with the subsequent decay of W+W−toﬁve partons and Z→swhere i and j denote jet indices and run from1to5.With the cuts listed above,W W Z production gives a background of less than one event with a luminosity of100fb−1and is thus small.This estimate is based on the nar-row width approximation[10];the deviation between the narrow width approximation and a more reﬁned treatment[11]is not large enough to aﬀect this estimate.Nonetheless, to be conservative we estimate one background event from W W Z production.Estimating the background from(Z+5jet)production is more tricky due to the huge number of diﬀerent graphs involved.Furthermore,large NLO QCD corrections may be expected in multi-partonﬁnal states[12].Rather than attempt an exact calculation (which would be beyond the scope of this letter),we will use the numerical results for 6jet production[12]to put an upper bound on this background.The cross-section for 6jet production at√3M tan2θW≃0.5M.The LEP experiments disfavored small tanβvalues[13].The SUSY explanation of the recently reported value of the muon anomalous magnetic moment also requires a large tanβand a positiveµ[14].In our calculation we choose the following representative set of values:M=150GeV,µ=300GeV,tanβ=10.(2) The chargino and neutralino masses in units of GeV are then given bym˜χ+1=133,m˜χ+2=328,m˜χ01=72,m˜χ02=134,m˜χ03=308,m˜χ04=327.(3)It should be remarked that SUSY parameters are generally not well-constrained ex-perimentally at the present time.The only robust constraints are the LEP and Tevatron lower bounds on some of the sparticle masses.Therefore,the above SUSY parameter25218983 6.9.01100120140160180s=500GeV.The standard model backgrounds can be minimized with suitable cuts leading to discovery bounds about as stringent as at the LHC[9]. AcknowledgmentsThis work was supported in part by DOE grant No.DE-FG02-94ER40817. References[1]P.Fayet,Phys.Lett.B69,489(1977);G.R.Farrar and P.Fayet,Phys.Lett.B76,575(1978).[2]G.’t Hooft,Phys.Rev.Lett.37,8(1967);Phys.Rev.D14,242(1976).[3]G.Bhattacharyya,hep-ph/9709395;H.Dreiner,hep-ph/9707435;S.Raychaud-huri,hep-ph/9905576;R.Barbier et al,hep-ph/9810232;B.Allanach et al,hep-ph/9906224.[4]J.Bagger et.al.hep-ex/0007022;R.Frey et.al.hep-ph/9704243.[5]A.Datta,J.M.Yang,B.-L.Young and X.Zhang,Phys.Rev.D56,3107(1997);R.J.Oakes,K.Whisnant,J.M.Yang,B.-L.Young and X.Zhang,Phys.Rev.D57, 534(1998);P.Chiappetta,A.Deandrea,E.Nagy,S.Negroni,G.Polesello,J.M.Virey,Phys.Rev.D61,115008(2000);K.-I.Hikasa,J.M.Yang,B.-L.Young, Phys.Rev.D60,114041(1999).[6]T.Han and M.B.Magro,Phys.Lett.B476,79(2000);L.Navarro,W.Porod,andJ.W.F.Valle,Phys.Lett.B459,615(1999);F.Campos,et al.,hep-ph/9903245;D.Atwood,talk at“Thinkshop On Top Quark Physics Of Run II”,FNAL,Oct.16-18,1998(web address /thinkshop/).[7]M.Dine,A.Kagan,and S.Samuel,Phys.Lett.B243,250(1990);S.Dimopoulosand G.F.Giudice,Phys.Lett.B357,573(1995);A.Pomarol and D.Tommasini, Nucl.Phys.B466,3(1996);A.Cohen,D.B.Kaplan,and A.E.Nelson,Phys.Lett.B388,599(1996).N.Arkani-Hamed and H.Murayama,Phys.Rev.D56, R6733(1997).[8]CDF collaboration,Phys.Rev.D56,R1357(1997).[9]K.J.Abraham,K.L.Whisnant,J.-M.Yang,&B.-L.Young;Phys.Rev.D63,034011(2001).[10]G.Belanger&F.Boudjema,Phys.Lett.B288,201(1992).[11]E.Accomando,A.Ballestero&M.Pizzio,Nucl.Phys.B512,19(1998).[12]S.Moretti,Phys.Lett.B420,367(1998).[13]See,e.g.,the L3collaboration,hep-ex/0012017.[14]see,e.g,A.Czarnecki and W.J.Marciano,hep-ph/0102122.[15]J.M.Yang,hep-ph/9905486;G.Bhattacharyya,J.Ellis and K.Sridhar,Mod.Phys.Lett.A10,1583(1995);G.Bhattacharyya,D.Choudhury and K.Sridhar,Phys.Lett.B355,193(1995).Figure1:The discovery(5σ)limits ofλ′′313versus sbottom mass.The region aboveeach curve is the corresponding region of discovery.Figure2:Same as Fig.1,but for the exclusion(2σ)limits.The region above eachcurve is the corresponding region of exclusion.Figure3:Same as Fig.2,but for the branching ratio of the B-violating decay t→˜¯b¯d.。