document: supersymmetry ( susy ) is one of the most attractive extensions of the standard model . 
   this symmetry solves the naturalness problem and predicts gauge coupling unification at the gut scale @xmath1 . 
   it also predicts the existence of superpartner of the standard model ( sm ) particles . from the naturalness argument , their masses should be below tev range , hence these particles will be discovered at tevatron or large hadron collider ( lhc ) 
   .    mechanisms of susy breaking and its mediation to the minimal supersymmetric standard model ( mssm ) sector are one of the most important problems in the susy phenomenology . in many models , 
   this dynamics is related to high energy physics far above the electroweak(ew ) scale , e.g. , gut scale or planck scale . 
   once the mechanism is specified , mass spectrum and flavor structure of susy particle at the ew scale can be determined by a small number of parameters . 
   hence it may be possible to confirm or exclude the mechanism by direct search or flavor - changing - neutral - current ( fcnc ) experiments in near future . 
   if susy breaking is mediated by gravity , the structure of susy breaking masses of scalars are determined by khler potential . in the present paper , 
   we focus on the no - scale type khler potential , in which the hidden sector and the observable sector are separated as follows : @xmath2 where @xmath3 and @xmath4 are hidden sector fields and observable sector fields , respectively 
   . this type of khler potential is originally investigated in ref . 
   @xcite with @xmath5 and @xmath6 . 
   characteristic features of the khler potential eq.([eq : noscalekahler ] ) is that all scalar masses and trilinear scalar couplings ( a - terms ) vanish as the cosmological constant vanishes@xcite . 
   the only source of susy breaking is gaugino masses . 
   hence this scenario is highly predictive , various phenomenological consequences are obtained with a few parameters . the separation in eq.([eq : noscalekahler ] ) implies that couplings of the hidden sector and the observable sector is flavor blind , and contributions of susy particles to fcnc are suppressed . 
   therefore this khler potential is also interesting from the viewpoint of the susy flavor problem . 
   the no - scale structure of the khler potential is obtained in various models . 
   it has been shown that in some classes of string theory , for example weakly coupled @xmath7 heterotic string theory , khler potential becomes the no - scale type@xcite . if the hidden sector and the observable sector are separated in the superspace density in the supergravity lagrangian , the khler potential is indeed given as in eq . 
   ( [ eq : noscalekahler ] ) . in the two cases , 
   the gaugino masses can be induced if the hidden sector fields couple to the gauge multiplets via the gauge kinetic function . 
   recently it has been pointed out that the form eq.([eq : noscalekahler ] ) is realized naturally in a five - dimensional setting with two branes , namely , sequestered sector scenario@xcite . in this scenario , 
   the hidden sector fields live on one brane and the visible sector fields live on the other . 
   it has been shown that the form of the khler potential of the effective theory obtained by dimensional reduction is indeed eq.([eq : noscalekahler])@xcite . 
   if the sm gauge fields dwell in the bulk , gaugino mediate the susy breaking on the hidden sector brane to the visible sector brane and the no - scale boundary condition is given at the compactification scale of the fifth dimension ( gaugino mediation @xcite ) .    in the no - scale scenario , degrees of freedom of susy particle mass spectrum 
   is limited because only non - zero soft susy breaking masses are gaugino masses and higgs mixing mass @xmath8 at the energy scale where the boundary condition is given . hence phenomenological aspects of this scenario have been investigated in the literature , mainly focusing on the mass spectrum . 
   direct search bounds and the cosmological constraint ( i.e. , a charged particle can not be the lsp if the r - parity is conserved ) were considered and allowed region in the parameter space was identified . for the boundary condition , 
   the following three cases were considered . 
   first , universal gaugino masses are given at the gut scale . 
   in this case , the cosmological constraint is severe and only the region @xmath9 and @xmath10 is allowed since stau tends to be light@xcite . 
   the second case is that universal gaugino masses are given above the gut scale . 
   and the third case is that non - universal gaugino masses are given at the gut scale . in this case wino , 
   higgsino or sneutrino can be the lsp . in the latter two cases , 
   it is shown that the cosmological constraint is not severer than the first case .    in the present paper , 
   current limits from the lightest higgs mass @xmath11 and the branching ratio for @xmath0 are also used to constrain the no - scale scenario . combining these constraints 
   , we will show that almost all the parameter region is excluded when universal gaugino masses are given at the gut scale . 
   however , when the boundary condition is given above the gut scale , relatively large parameter region is allowed . 
   we also consider the case that the non - universal gaugino masses are given at the gut scale . 
   we will show that these constraints are important when the higgsino - like neutralino is the lsp . 
   this paper is organized as follows . in section [ sec : noscalsebc ] , we review some phenomenological aspects of the no - scale models , especially indications of the direct search bounds and the cosmological bound . in section [ sec : higgsbsgamma ] , we further constrain these models from the higgs mass bound and @xmath12 result . indications of these bounds for the tevatron are also discussed . 
   our conclusions are given in section [ sec : conclusions ] . 
   in this section , we briefly review phenomenological aspects of susy models with no - scale boundary condition , mainly indications of the cosmological bound and direct search limit at lep 2 . 
   we consider the following three cases .    * 
   universal gaugino masses are given at the gut scale . 
   hereafter we call this case the minimal scenario . * 
   universal gaugino masses are given above the gut scale @xmath13 . throughout this paper 
   , we take the minimal su(5 ) to be the theory above the gut scale as a typical example . * 
   non - universal gaugino masses are given at the gut scale . 
   once one of the above boundary conditions is given , mass spectrum of susy particles at the ew scale and their contributions to fcnc can be calculated . in this paper 
   we solve the one - loop level rges to obtain the soft susy breaking mass parameters at the ew scale . 
   the higgsino mass parameter @xmath14 is determined by potential minimum condition at the one - loop level . 
   first , we discuss the minimal scenario . in this case 
   , the following boundary condition is given at the gut scale , @xmath15 where @xmath16 is the common scalar mass and @xmath17 is universal trilinear scalar coupling . with this boundary condition , bino and right - handed 
   sleptons are lighter than other susy particles . 
   their masses are approximately , @xmath18 from eq.([eq : minimalmneumtau ] ) we see that the charged right - handed slepton is the lsp if the d - term @xmath19 is negligible , i.e. , @xmath20 . 
   hence this parameter region is excluded by the cosmological consideration . on the other hand , 
   lep 2 experiments yields the upper bound on the cross section for smuon pair production , @xmath21 for @xmath22 and @xmath23@xcite , so the parameter region @xmath24 is excluded in fig . 
   [ fig : limitmimposmu ] and [ fig : limitmimnegmu ] , allowed region of the parameter space are shown in the @xmath25 plane . 
   the regions above the dash - dotted line and the left side of the dash - dot - dotted line are excluded by cosmological bound and lep 2 bound on smuon pair production , respectively . 
   therefore the minimal scenario is constrained severely . 
   next we see the case that the universal gaugino masses are given above the gut scale . in the minimal su(5 ) case , the right - handed slepton belongs to 10-plet , so the large group factor makes slepton masses heavier . 
   for example , when @xmath26 the bino mass and the right - handed slepton mass at the weak scale are approximately given , @xmath27 hence the cosmological constraint is not severe because the stau mass is large enough and neutralino is the lsp in the large parameter region @xcite . in the fig.[fig : limitmbc1e17posmu ] and [ fig : limitmbc1e17negmu ] , the same figures as in the fig.[fig : limitmimposmu ] and [ fig : limitmimnegmu ] are shown . 
   unlike in the minimal case , the stau search bound at lep @xcite is also plotted because mass difference between @xmath28 and @xmath29 is larger than in the minimal case and it can be stronger than the smuon search . from these figures we see that the @xmath29 lsp is avoided unless @xmath30 is larger than about 20 . 
   the charged stau lsp can also be avoided if gaugino masses at the gut scale are non - universal@xcite , i.e. , the following boundary condition is given , @xmath31 this boundary condition can be given naturally within the gut framework @xcite . in this case , 
   not only bino - like neutralino , but also wino - like , higgsino - like neutralino or sneutrino can be the lsp . for @xmath32 and @xmath33 , 
   the lsp is wino - like neutralino . 
   for example , when @xmath34 and @xmath35 , then wino mass and charged slepton mass are ( notice that in this case the left - handed sleptons are lighter than right - handed sleptons ) ; @xmath36 the higgsino is the lsp if @xmath37 . for example , when @xmath38 and @xmath39 , then the higgsino mass and the right - handed slepton mass are @xmath40 in the two cases given above , neutral wino or higgsino is the lsp . 
   in fact from fig.[fig : limit12r432r2posmu ] - [ fig : limit12r232r0.5negmu ] we find that neural particle is the lsp in large parameter region , thus it is cosmologically viable . 
   in the previous section we take into account only lep 2 bound and the cosmological constraint . 
   we find that the minimal scenario is severely constrained , but the other two scenarios are not . in this section 
   we also include the current higgs mass bound and @xmath41 constraint . 
   as we will see , combining the above four constraint , not only the minimal case but also the other two scenarios can be constrained more severely . 
   we also discuss the possibility whether this scenario can be seen at the tevatron run 2 or not . 
   before we show the numerical results , some remarks on our calculation of the higgs mass and @xmath12 are in order . 
   it is well known that radiative correction is important when the lightest higgs mass is evaluated @xcite . in the present paper , 
   the lightest higgs mass is evaluated by means of the one - loop level effective potential@xcite . 
   this potential is evaluated at the renormalization point of the geometrical mean of the two stop mass eigenvalues @xmath42 . 
   we compared our result with a two - loop result by using _ 
   feynhiggs_@xcite , and checked that the difference between these two results is smaller than 5 gev as long as @xmath30 is bigger than 5 . 
   when @xmath30 is close to 2 , the difference can be 7 gev . 
   however , as we will see later , higgs mass bound plays an important rule around @xmath43 . and 
   the two - loop effects always make the higgs mass lighter than that obtained at the one - loop level . 
   so our conclusion is conservative and is not significantly changed by the two - loop effect . 
   we exclude the parameter region where the lightest higgs mass is lighter than the current 95% c.l . 
   limit from lep 2 experiments , @xmath44 @xcite .    in the present paper , @xmath12 
   is calculated including leading order ( lo ) qcd corrections@xcite , and compare it to the current cleo measurement . in the mssm 
   , chargino contribution can be comparable to the sm and charged higgs contributions . 
   they interfere constructively ( destructively ) each other when @xmath45 ( @xmath46 ) . 
   the difference between the lo and the next - to - leading order ( nlo ) result can be sizable only when cancellation among different contributions at the lo is spoiled by the nlo contributions . 
   as we will see , however , the @xmath41 constraint is severe when the interference is constructive . in the case of destructive interference where the deviation from the nlo result may be large , 
   this constraint is not so important . 
   hence we expect that our conclusion is not changed significantly by the inclusion of the nlo corrections . for the experimental value 
   , we use 95% c.l . 
   limit from cleo , @xmath47 @xcite . 
   first we show the numerical results for the minimal case . 
   the case for @xmath48 is shown in fig.[fig : limitmimposmu ] . in this case , for small @xmath30 region , the stop mass is not so large that radiative correction factor @xmath49 which raises the higgs mass is small . 
   ( for example , @xmath50 gev and @xmath51 gev for @xmath52 gev and @xmath53 ) . 
   hence the higgs mass limit constrains this scenario severely . in fig.[fig : limitmimposmu ] , the higgs mass bound and @xmath12 constraints in the @xmath54 plane are shown . 
   the regions below the solid line and above the dashed line are excluded by the higgs mass and @xmath12 bound , respectively . 
   the indication of @xmath55 reported by lep 2@xcite is also shown in this figure . from the figure we find that the higgs mass bound almost excludes the region where the stau lsp is avoided . 
   note that , as we discussed earlier , the bound we put on the higgs mass may be conservative , because the two loop correction may further reduce the higgs mass .    the same figure but for @xmath56 is shown in fig.[fig : limitmimnegmu ] . 
   now @xmath12 also constrains parameter region strongly since chargino contribution to @xmath0 interferes with sm and charged higgs ones constructively . 
   the region above the dashed line is excluded by @xmath12 constraint . 
   we find that only one of the two constraints is enough to exclude all the region where cosmological bound and the smuon mass bound are avoided . 
   hence if r - parity is conserved , i.e. , the cosmological bound is relevant , this scenario with @xmath56 is excluded . 
   next we show the numerical results in the case that the cutoff scale is larger than the gut scale . as a typical example , we choose the minimal su(5 ) as the theory above the gut scale . in fig.[fig : 
   limitmbc1e17posmu ] and [ fig : limitmbc1e17negmu ] , results are shown for positive and negative @xmath14 , respectively . in both figures , 
   we take @xmath58 gev . for @xmath48 case , large parameter region 
   is allowed and susy scale @xmath59 can be as small as about 180 gev , which indicates the lsp mass @xmath60 gev . for @xmath56 , as in the minimal case , @xmath12 constraint is severer , and @xmath59 must be larger than around 280 gev . 
   we also considered other values of the boundary scale @xmath61 from @xmath62 to @xmath63 , and checked that the behavior of the contour plot does not change so much . 
   according to ref.@xcite , tevatron run 2 experiment can explore up to @xmath64 gev for integrated luminosity @xmath65 . 
   hence if @xmath66 and @xmath67 , susy particles can be discovered at the experiment . in this range , 
   trilepton from chargino - neutralino associated production @xmath68 , @xmath69 , @xmath70 is one of clean signals for susy search . 
   notice that now two body decay @xmath71 opens . 
   so same flavor , opposite sign dilepton from @xmath72 decay may be useful . 
   the two body decay allows us to observe the peak edge of invariant mass of two leptons at the @xmath73 . 
   it is expressed in terms of the neutralino masses and the slepton mass as , @xmath74 in table [ tab : mllmax ] , the dependence of @xmath73 on @xmath61 is shown . here 
   we fix @xmath75 . 
   notice that as @xmath61 changes , the right - handed mass changes sizably while the neutralino masses do not . 
   hence we can obtain the mass relation among them and also cutoff scale @xmath61 , which corresponds to the compactification scale in the sequestered sector scenario , by measuring @xmath73 . on the other hand , since only @xmath76 gev is allowed for @xmath45 , the tevatron run 2 can not survey this scenario , and we have to wait lhc experiment . 
   next , we turn to the case that gaugino masses are non - universal at the gut scale . 
   we explore the following three cases , wino - like neutralino lsp , higgsino - like neutralino lsp and the tau sneutrino lsp . 
   we will see that in the wino - like neutralino lsp and tau sneutrino lsp cases , constraint is not so severe even if we combine higgs mass bound and @xmath12 data , but in the higgsino - like lsp case where stops are as light as sleptons and charginos , the predicted higgs mass tends to be small , and thus the higgs mass bound becomes important . 
   first , we discuss the wino - lsp case . 
   the results for @xmath34 , @xmath35 are shown in fig.[fig : limit12r432r2posmu ] and fig.[fig : limit12r432r2negmu ] , for @xmath46 and @xmath45 , respectively . in this case , we obtain a relatively large higgs mass since @xmath77 is large and so are the masses of stops . 
   hence , for @xmath46 , @xmath78 can be as small as 100 gev at @xmath43 , where the mass of the lsp @xmath79 is about 90 gev . for @xmath45 
   , though @xmath12 constraint is slightly severer than in the @xmath46 case , @xmath80 is allowed , which corresponds to @xmath81 . 
   hence the wino - lsp with mass around 100 gev is allowed . 
   examples of the mass spectrum in this case are listed as point a ( @xmath46 ) and point b ( @xmath45 ) in table [ tab : spectrum ] . at the both points , 
   @xmath59 is chosen to be near the smallest value such that all constraints are avoided . 
   in general , however , masses of @xmath28 and @xmath82 are highly degenerate when wino is the lsp . 
   in fact , from table [ tab : spectrum ] , we see that the mass difference is less than 1 gev . 
   therefore a lepton from @xmath70 is very soft and trilepton signal search is not useful because acceptance cut usually requires the smallest transverse momentum of the three leptons @xmath83 to be larger than 5 gev@xcite . 
   recently collider phenomenology in such cases are studied in ref . 
   it is shown that certain range of @xmath84 and @xmath85 , susy signals which are different from those in the minimal case can be detected . 
   the high degeneracy requires to include radiative corrections to calculate @xmath85 @xcite , which is beyond of this work . 
   it deserves detail study to estimate the mass difference in the scenario . 
   since the constraint for the sneutrino lsp case in the @xmath86 plane is similar to those in the wino - lsp case , we show the result for @xmath46 only in fig.[fig : limit12r2.532r1.5posmu ] . in the figure 
   , we take @xmath87 and @xmath88 . 
   notice that the decomposition of the lsp depends on @xmath30 and the sneutrino is the lsp for @xmath89 . 
   an example of the mass spectrum is listed as the point c in table [ tab : spectrum ] . in this case , 
   trilepton signal comes from @xmath90 , @xmath91 , @xmath92 . 
   since @xmath93 , @xmath94 of a lepton from @xmath82 decay is small and this signal may be hard to be detected . 
   we may need unusual trigger to explore this scenario . 
   next , we turn to the higgsino lsp case . 
   higgsino lsp scenario is realized when @xmath77 is smaller than half of @xmath78 , which indicates that colored particles are lighter than in the universal gaugino mass case . 
   hence the one - loop correction to the higgs potential which enhances the higgs mass is small and the higgs mass constraint is important . the same figures as fig.[fig : limitmimposmu ] and [ fig : limitmimnegmu ] are shown in fig.[fig : limit12r232r0.5posmu ] ( @xmath46 ) and fig.[fig : limit12r232r0.5negmu ] ( @xmath45 ) for @xmath95 and @xmath39 . in order to satisfy the higgs mass bound , @xmath78 must be larger than around 300 gev . 
   combining the bound with @xmath12 , constraint becomes severer , especially for @xmath45 case where @xmath96 is required . 
   example of mass spectrum in this scenario is listed as point d and e in table [ tab : spectrum ] . 
   again we choose almost the smallest value of @xmath78 where all constraints are avoided . 
   we see that the lsp mass must be at least @xmath97 for @xmath46 and @xmath98 for @xmath45 . 
   hence this scenario can not be explored at the tevatron run 2 . 
   the no - scale type boundary conditions are obtained in various types of susy models . 
   this scenario is attractive because it is highly predictive and can be a solution to the susy flavor problem . in this paper 
   we investigated the indication of the current higgs mass and @xmath41 constraint on susy models with the boundary condition . 
   first we considered the minimal case where the universal gaugino mass are given at the gut scale . 
   this scenario has been already constrained by direct search at lep and the cosmological bound severely , under the assumption of the exact r - parity . 
   we showed that the higgs mass bound and @xmath41 constraint are also taken into account , then almost all the parameter region is excluded , leaving very narrow allowed region for @xmath48 . 
   next we considered the case that the boundary condition is given above the gut scale . 
   since the cosmological constraint is not severe , wide region of the parameter space is allowed . in the @xmath46 case , 
   tevatron have a chance to observe susy signatures like trilepton events . 
   the scale @xmath61 may be explored by measuring the peak edge of invariant mass of two leptons at the @xmath73 . 
   however for the @xmath45 case , since @xmath99 is required , we have to wait lhc . 
   finally we considered the case where non - universal gaugino masses are given at the gut scale . 
   we see that the higgs mass bound is strong in the higgsino lsp case because stop masses are as light as sleptons and charginos . 
   the mass of the higgsino - like neutralino must be larger than about 245 gev and 370 gev for @xmath46 and @xmath45 , respectively . in the wino lsp and sneutrino lsp case 
   , the mass of the lsp can be as small as 150 gev . 
   however , the mass difference between the lsp and parent particles produced at the collider is much smaller than in the minimal case , unusual acceptance cut may be required . 
   the author would like to thank m. yamaguchi for suggesting the subject , fruitful discussion and careful reading of the manuscript . 
   he also thanks t. moroi and m. m. nojiri for useful discussion . 
   j. ellis , c. kounnas and d.v . 
   nanopoulos , nucl . 
   b247 ( 1984 ) 373 ; j. ellis , a.b . 
   lahanas , d.v . 
   nanopoulos and k. tamvakis , phys . 
   b134 ( 1984 ) 439 ; a.b . 
   lahanas and d.v . 
   nanopoulos , phys . 
   ( 1987 ) 1 . 
   e. witten , phys . 
   b155 ( 1985 ) 151 . 
   t. banks and m. dine , nucl . 
   b505 ( 1997 ) 445 ; h.p . 
   nilles , m. olechowski and m. yamaguchi , phys . 
   b415 ( 1997 ) 24 ; nucl . 
   phys . b530 
   ( 1998 ) 43 ; z. lalak and s. thomas , nucl . 
   phys . b515 
   ( 1998 ) 55 ; a. lukas , b.a . 
   ovrut and d. waldram , nucl . 
   phys . b532 
   ( 1998 ) 43 ; phys . 
   d57 ( 1998 ) 7529 ; k. choi , h.b . 
   kim and c. muoz , phys . 
   d57 ( 1998 ) 7521 . 
   y. okada , m. yamaguchi and t. yanagida , prog . 
   85 ( 1991 ) 1 , phys . 
   b262 ( 1991 ) 54 ; j. ellis , g. ridolfi and f. zwirner , phys . 
   b257 ( 1991 ) 83 ; h. e. haber and r. hempfling , phys . 
   66 ( 1991 ) 1815 . 
   aleph collabolation , phys . 
   b495 ( 2000 ) 1 ; l3 collabolation , phys . 
   b495 ( 2000 ) 18 ; delphi collabolation , phys . 
   b499 ( 2001 ) 23 ; opal collabolation , phys . 
   b499 ( 2001 ) 38 ; p. 
   igo - kemenes , talk at the lepc open session on nov . 
   3rd , http://lephiggs.web.cern.ch/lephiggs/talks/index.html . 
   plane for the minimal case with @xmath48 . in the region above the dash - dotted line , the stau is the lsp . 
   the left side of the dash - dot - dotted line is excluded by the upper bound on smuon pair production cross section at lep . 
   the current higgs mass bound excludes the region below the solid line . in the region above the dashed line , @xmath12 is smaller than the lower limit obtained by the cleo . 
   the shaded region is allowed . 
   the @xmath100 curve is also shown as the dotted line . 
   noewsb means that radiative breaking does not occur.,width=340,height=264 ]     but @xmath56 . 
   the region above the dashed line is excluded since @xmath12 is larger than the upper limit obtained by the cleo . 
   the other lines are the same as in fig.[fig : limitmimposmu ] . 
   notice that all region is excluded.,width=340,height=264 ]     plane for universal gaugino masses , @xmath26 and @xmath48 . 
   the left sides of the dash - dot - dotted and dash - dot - dot - dotted line are excluded by the upper bound on the smuon and stau pair production cross section , respectively . 
   the other lines are the same as in fig.[fig : limitmimposmu ] , width=340,height=264 ]             plane for the higgsino lsp case , @xmath95 , @xmath39 , @xmath101 and @xmath48 . in the region between the two dashed line , 
   @xmath12 is smaller than the lower limit of the cleo result . 
   , width=340,height=264 ]
summary: no - scale structure of the khler potential is obtained in many types of supersymmetric models . in this paper , 
   phenomenological aspects of these models are investigated with special attention to the current higgs mass bound at lep and @xmath0 result at the cleo . 
   when the boundary condition is given at the gut scale and gaugino masses are universal at this scale , very narrow parameter region is allowed only for positive higgsino mass region if r - parity is conserved . 
   the negative higgsino mass case is entirely excluded . on the other hand , relatively large parameter region 
   is allowed when the boundary condition is given above the gut scale , and tevatron can discover susy signals for the positive higgsino mass case . 
   the no - scale models with wino , higgsino or sneutrino lsp are also considered . 
   we show that the higgs mass constraint is important for the higgsino lsp case , which requires the lsp mass to be larger than about 245 gev . 
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