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Supersymmetric virtual effects in heavy quark pair production at LHC

a r

:h e

PM/04-01,corrected version

Supersymmetric virtual e?ects in heavy quark pair production at LHC ?M.Beccaria a,b ,F.M.Renard c and C.Verzegnassi d,e a Dipartimento di Fisica,Universit`a di Lecce Via Arnesano,73100Lecce,Italy.b INFN,Sezione di Lecce c Physique Math′e matique et Th′e orique,UMR 5825Universit′e Montpellier II,F-34095Montpellier Cedex 5.d Dipartimento di Fisica Teorica,Universit`a di Trieste,Strada Costiera 14,Miramare (Trieste)e INFN,Sezione di Trieste Abstract We consider the production of heavy (b,t )quark pairs at proton colliders in the theoretical framework of the MSSM.Under the assumption of a ”moderately”light SUSY scenario,we ?rst compute the leading logarithmic MSSM contributions at one loop for the elementary processes of production from a quark and from a gluon pair in the 1TeV c.m.energy region.We show that in the initial gluon pair case (dominant in the chosen situation at LHC energies)the electroweak and the strong SUSY contributions concur

to produce an enhanced e?ect whose relative value in the cross sections

could reach the twenty percent size for large tan βvalues in the realistic

proton-proton LHC process.

PACS numbers:12.15.-y,12.15.Lk,13.75.Cs,14.80.Ly

Typeset using REVT E X

I.INTRODUCTION

One of the main goals of the future experiments at hadron colliders will be undoubtedly the search for supersymmetric particles.In the speci?c theoretical framework of the MSSM,a vast amount of literature already exists showing the expected experimental reaches for the di?erent supersymmetric spectroscopies and parameters,both for the TEVATRON[1]and for the LHC[2]cases.For what concerns the possibility of direct production,nothing has to be added(in our opinion)to the existing studies,leading to the conclusion that,if any supersymmetric particle exists with a not unfairly large mass, it will not escape direct detection and identi?cation.

A nice and special feature of the present and future hadron colliders is the fact that, on top of direct SUSY production,a complementary precision test of the involved model (assuming

II.INITIAL qˉq STATE

We begin our analysis at the partonic level considering as initial states the light quark components of the proton(including the bottom component but ignoring the top quark one).At lowestαs order the scattering amplitude is given by the Born terms schemati-cally represented in Fig.1.The s-channel diagram of Fig.1a applies to all initial qˉq pair annihilation and leads to:

A Born

= i,j a Born s ij[ˉv(ˉq)λlγμ2P j v(ˉq′)](2.1)

whereas the t-channel diagram will only apply to bˉb→bˉb scattering(because we shall neglect the tˉt→tˉt contribution)and writes:

A Born

= i,j a Born t ij[ˉv(ˉq)λlγμ2P j u(q)](2.2) where i,j refer to R or L quark chiralities with P R,L=1±γ5

s a Born t

4παs

is,at least,supported by the fact(that we showed in a previous paper[7])that such terms at lepton colliders(LC)are only requested if the available c.m.energy of the process is beyond,roughly,the1TeV range.In our investigation of proton colliders,the structure of the leading electroweak corrections is essentially similar to the LC one(with straight-forward modi?cations of the initial vertex contributions).To reproduce the bene?t of the absence of hard resummation computations,we shall therefore be limited to c.m.energy values not beyond the1TeV limit.

Having?xed the considered energy range,a numerical evaluation at one loop can now be performed in a(reasonably)straightforward way.A great simpli?cation can nonetheless be achieved under the assumption that the c.m.energy is su?ciently larger than all the masses of the(real and virtual)particles involved in the process.In this case, a logarithmic expansion of the so-called Sudakov kind can be adopted.All the details of such an approach for the speci?c MSSM model have been already exhaustively discussed in previous references for an initial electron-positron state[8],[9],but the results are essentially identical if the initial state is a qˉq pair(as we said,one must only modify in a straightforward way the initial vertex contribution).To avoid loss of space and time,we defer thus the reader to[8],[9]for details.The only relevant point that we want to make is the fact that the”canonical”logarithmic expansion is given to next-to leading order,i.e.retaining the double and the linear logarithmic terms,and ignoring possible extra(e.g.constant)contributions.To this level,the remarkable simpli?cation for the considered heavy quark?nal state is that only two SUSY parameters appear in the expansion.One parameter is tanβ,contained in the coe?cient of the linear ln of Yukawa origin;the second one is a(common)SUSY mass scale M,to be understood as an”average”supersymmetric mass involved in the process.

Given the fact that the supersymmetric masses might be not particularly small(the existing limits for squark and gluino masses are at the moment consistent with a lower bound of approximately300GeV[1],[10])and taking into account the qualitative1TeV upper bound on the c.m.energy requested for the validity of a one-loop expansion,we shall adopt in this preliminary analysis a reasonable working compromise.In other words, we shall consider energy values in the1TeV range,and a SUSY scenario”reasonably”light i.e.one in which all the relevant SUSY masses of the process are smaller than, approximately,350?400GeV.This will encourage us to trust a conventional Sudakov expansion,supported by previous detailed numerical analyses given for electron-positron accelerators[11].

The previous discussion was related to the SUSY electroweak e?ects.Our attitude will be in conclusion that of considering both the SM and the SUSY components at the same one loop level.Strictly speaking,since we are only interested in the SUSY e?ect, we could even ignore the SM contribution.The reason why we retain it is simply that it is easy to estimate it and interesting to show the”SUSY enhancement”in the MSSM overall correction.

After this long but,we hope,su?ciently clear discussion,we are now ready to illus-trate the one-loop numerical details.With this aim,we shall start from the electroweak diagrams of Fig.2and write,following our previous notations[7–9]:

Electroweak logarithmic corrections on the amplitudes

For each qˉq→q′ˉq′amplitude we can write,following ref.[9]:

A1loop ew=A Born[1+c ew](2.4) with

c ew≡c in,gauge+c in,Y uk+c fin gauge+c fin,Y uk+c ang(2.5) where c in refers to the universal(i.e.process independent)corrections due to the initial qˉq pair,c fin to the universal corrections due to the?nal bˉb or tˉt pair an

d c ang is a process and angular dependent correction typical of each qˉq→q′ˉq′case.Th

e Yukawa contributions are sizable only for q(or q′)being b or t quarks.The coe?cients c ew receive SM and SUSY contributions,depending on the quark chirality.The SM contributions are(u represents both up and charmed quarks,and d both down and strange quarks):

c uˉu SM

in,gauge L =c tˉt SM

fin,gauge L

α(1+26c2W)

M2W?ln2

9πc2W

[3ln

M2W

](2.6)

c dˉ

d SM

in,gauge L =c bˉb SM

fin,gauge L

α(1+26c2W)

M2W?ln2

36πc2W

[3ln

M2W

](2.7)

c bˉb SM

in,fin,Y uk L =c tˉt SM

in,fin,Y uk L

M2W

m2b

M2W

]

c bˉb SM

in,fin,Y uk R =?

M2W

][ln

8πs2W

[

m2t

M2W

](2.8)

c qˉq q′ˉq′SM ang ij =?

1+cosθ

][8Q q Q q′+2

g Z qi g Z fj

M2W

](2.9)

This last angular dependent term refers to chirality states(ij)=(LL,LR,RL,RR) and involves the quark charges Q q and the Zqˉq couplings g Z qL=I3qL(2?4|Q q|s2W), g Z qR=?2Q q s2W.

The additional SUSY contributions a?ect only the universal parts:

c uˉu SUSY in,gauge L =c tˉt SUSY

fin,gauge L

α(1+26c2W)

]

c uˉu SUSY in,gauge R =c tˉt SUSY

fin,gauge R

](2.10)

c dˉ

d SUSY in,gaug

e L =c bˉb SUSY

fin,gauge L

α(1+26c2W)

]

c dˉ

d SUSY in,gaug

e R =c bˉb SUSY

fin,gauge R

](2.11)

c bˉb SUSY

in,fin,Y uk L =c tˉt SUSY

in,fin,Y uk L

M2W

(1+2cot2β)+

m2b

]

c bˉb SUSY

in,fin,Y uk R =?

M2W

(1+2tan2β)][ln

8πs2W

[

m2t

](2.12)

One can see(as emphasized in ref.[9])that the total MSSM gauge correction is

quite simply obtained by replacing the logarithmic SM factor[3ln s

W ]by

[2ln s

W ]and the total MSSM Yukawa correction by replacing the SM m2t by

2m2t(1+cot2β)and m2b by2m2b(1+tan2β).

Results for angular distributions,averaged over initial,summed over?nal polarizations

We now list explicitely the complete MSSM results for each subprocess.According to the rules given just above it is easy to separate the pure SM and the additional SUSY parts.We?rst consider the subprocesses involving only the annihilation channel of Fig.1a and Fig.2,and write:

dσ1loop

dcosθ+

πα2s

dcosθ=

πα2s

For uˉu→bˉb

72πs2W c2W (54?32s2W)[2ln

M2W

]

?αM2

W (1+cot2β)+

3m2b

M2W

]

?α(4s2W?9)1+cosθ[ln s

2πs2W c2W ln

1?cosθ

M2W

](2.16)

For dˉd→bˉb

72πs2W c2W (54?44s2W)[2ln

M2W

]

?αM2

W (1+cot2β)+

3m2b

M2W

]

+α(8s2W?9)

1+cosθ

[ln

2πs2W c2W

1?cosθ

M2W

](2.18)

For uˉu→tˉt

36πs2W c2W (27?10s2W)[2ln

M2W

]

?αM2

W (1+cot2β)+

m2b

M2W

]

?α(16s2W+9)1+cosθ[ln s

2πs2W c2W ln

1?cosθ

M2W

](2.20)

For dˉd→tˉt

36πs2W c2W (27?16s2W)[2ln

M2W

]

?αM2

W (1+cot2β)+

m2b

M2W

]

?α(4s2W?9)1+cosθ[ln s

D dˉdtˉt=α

1+cosθ

[ln

S bˉbtˉt=

M2W?ln2

4πs2W

[

4m2t

M2W

(1+tan2β)][ln

18πs2W c2W

1?cosθ

M2W

](2.23) D bˉbtˉt=

1+cosθ

[ln

we have to add the annihilation amplitude of Fig.1a and

of Fig.2,and the scattering amplitude of Fig.1b and of the s→t crossed diagrams of Fig.2.This leads to the result

dσ1loop(bˉb→bˉb)

dcosθ{1+α

M2W?ln2

4πs2W [

m2t

M2W

(1+tan2β)][ln

18s [ln

9s2W c2W

)([

3st

]ln

1?cosθ

t2?u2

27?22s2W

t2?

?(4s2W s2ln1?cosθt2ln1+cosθ

dcosθ=

2πα2s

u2+s2

3st

](2.26)

In the expression(2.25),the?rst part(which factorizes the Born term)is the universal e?ect including the gauge term and the double Yukawa e?ect,whereas the second part is the angular dependent e?ect from s and from t channels(one can check,restricting to the1/s2terms,that one recovers the previous dˉd→bˉb case);the s→t crossing relation between annihilation and scattering contributions is also clearly satis?ed.

Having completed the discussion of the electroweak SUSY e?ect,we now move in the following subsection IIb to the discussion of the strong(QCD)SUSY correction.

B.QCD SUSY correction

A preliminary statement to be made before entering the discussion of the QCD SUSY corrections is that we shall treat this e?ect under the same assumptions that we adopted for the electroweak sector,subsection IIa.In other words,we shall still concentrate our analysis on c.m.energy values in the1TeV region,assuming the previously considered ”reasonably”light SUSY scenario.This will allow us to use the same kind of simple logarithmic expansion that was exploited in the electroweak case,at the one loop level.

For what concerns the expected validity of a one-loop perturbative expansion,the situation is now,though,drastically di?erent from that of subsection IIa,and requires a precise subtle choice of strategy.It is actually well-known[12]that,in the SM domain, the one-loop QCD correction is not accurate enough and higher order terms seem to be fundamental.This is understandable in an extremely simpli?ed fashion as a consequence of the small scale which enters the SM running ofαs.In this qualitative picture,one would expect that the corresponding SUSY e?ects do not share this dramatic problem, owing to the much larger mass scale involved.This would justify the expectation that,for the restricted subset of SUSY QCD corrections,a one-loop calculation can be su?cient.

Another essential di?erence between the SM QCD and the SUSY QCD corrections is that in the SM part the infrared logarithms arising from virtual gluon contributions cancel against those occurring in soft real gluon emission,leaving only”constant”terms.In the SUSY case,large logarithms of virtual origin and scaled by the average SUSY mass will remain.A practical attitude seems to be therefore that of isolating the SM higher order QCD e?ects,considering them as a”known”quantity,much in analogy with what is done for the canonical QED corrections,and to factorize an explicit one-loop term containing the genuine SUSY QCD correction,to be added in the usual one-loop philosophy to the electroweak one.This is the approach that we shall follow in the rest of the paper,which is,as we said,only interested in the evaluation of the genuine

3πln

vertex e?ect has a numerical value of approximately5percent at1TeV c.m.energy. This supports our assumption that higher order terms can be neglected,as we shall do in this paper.Note also that the size of the e?ect is smaller than that of the analogous electroweak component,particularly for large tanβvalues in the Yukawa couplings.In other words,at the one loop level,electroweak SUSY corrections appear to be”stronger”than the corresponding QCD ones,in full analogy with a similar feature?rst stressed in the electron-positron case[13].

From a practical point of view,the very welcome feature that characterizes the QCD SUSY vertex is the fact that the sign of the one-loop e?ect is the same

SUSY scales,it would lead to the following modi?cation:

δαSUSY

s (s)=αs(M2)[?B SUSY

αs(M2)

](2.29)

The SUSY contribution arising in the MSSM for s>M2is obtained using B SUSY=?2.This leads e?ectively to one more additional coe?cient in the series of corrections eq.(2.4,2.5)to the annihilation amplitude

c qˉq,SUSY QCD RG =?B SUSY

αs(M2)

(2.30)

and a similar correction to the scattering amplitude with ln(s/M2)replaced by ln(?t/M2).

Note that,in a less optimistic situation of larger SUSY masses,the e?ect would be reduced and should be computed more carefully.But,independently of this,we notice a less pleasant feature of eq.(2.30)compared to eq.(2.28)i.e.the fact that it produces an e?ect of opposite sign with respect to that of the electroweak one,thus reducing the overall SUSY correction:

A1loop SUSY=A Born[c SUSY ew+c SUSY QCD](2.31) with

c SUSY QCD??2αs M2+αs M2=αs M2(2.32)

From this point of view,the qˉq initial state exhibits a”disturbing”feature for the detection of SUSY e?ects.This feature will not

III.INITIAL gg STATE

The amplitude for the process g i g j→q′ˉq′(where i,j denote the gluon color states)is obtained by summing the2diagrams of Fig.4a,b and the crossed diagram of Fig.4b:

A Born

s =?i

g2s

γμ(k i?k j)μv(ˉq′)](3.1)

A Born

t =?

g2s

(γμ?iμ)(γρ(k i?p q′)ρ)(γν?jν)v(ˉq′)](3.2)

A Born

u =?

g2s

(γμ?jμ)(γρ(k i?pˉq′)ρ)(γν?iν)v(ˉq′)](3.3)

where s=(k i+k j)2=(p q′+pˉq′)2,t=(k i?p q′)2,u=(k i?pˉq′)2,and(?i,k i),(?j,k j)are the polarization vectors and four-momenta of the gluons.

It is important to notice the gauge cancellations occurring at high energies.From the above expressions one can immediately compute the helicity amplitudes F(τi,τj,λq′,λˉq′) withτi=±1,τj=±1,λq′=±1/2,λˉq′=±1/2being the gluons and quark helicities. At high energy,neglecting quark masses,one obtains only chirality conserving terms with λq′=?λˉq′≡λ=±1/2.The contribution to the amplitudes withτi=?τj≡τ=±1 arises from t and u channel terms:

F Born(τ,?τ,λ,?λ)=g2s(λiλj

1?cosθ

sinθ+g2s(

λjλi

1+cosθ

sinθ(3.4)

whereas theτi=τj≡τ=±1amplitudes get contributions from s,t and u channel terms:

F Born(τ,τ,λ,?λ)=?ig2s f ijk λk

)(2λ)sinθ?g2s(

λjλi

4?λjλi2.

So,at high energy,we are only left with contributions to F Born(τ,?τ,λ,?λ)arising from the t and u channel quark exchange diagrams,λ=±1/2corresponding to R,L chiralities respectively.

The electroweak corrections are then extremely simple.At?rst order no electroweak correction arises for gluons.Only the universal gauge and Yukawa terms appear for the ?nal b or t quark pair:c q′ˉq′fin,gauge L,R and c q′ˉq′fin,Y uk L,R from eq.(2.5).

The SUSY QCD corrections turn out to be also extremely simple.Because of the gauge cancellation of the s channel term,at?rst order we can ignore the SUSY QCD corrections to this part and only consider the t and u channel quark exchange diagrams, Fig.1b and Fig.5.There is no SUSY QCD correction to the external gluon lines because of the cancellation between the gluon splitting function and the gluon coupling Parameter Renormalization(this fact is similar to the one occurring for electroweak gauge bosons as

noticed in ref.[14,15]).Only the universal SUSY QCD correction to the external quark

lines appear,given by c q′ˉq′SUSY QCD

L,R of eq.(2.27).

The angular distributions averaged over initial gg,summed over?nal b,ˉb or t,ˉt polar-izations are then given by

dσ1loop(gg→bˉb)

dcosθ{1+α

M2W?ln2

8πs2W [

m2t

M2W

(1+tan2β)][ln

3π

[ln

dcosθ=

dσBorn(gg→tˉt)

144πs2W c2W

(27?10s2W)[2ln

M2W

]

?αM2

W (1+cot2β)+

m2b

M2W

2αs

]}(3.7)

In the above expression we have written the complete MSSM electroweak correction and the SUSY QCD correction.In the MSSM electroweak part one can easily separate the pure SM and the SUSY components using the rules already stated in the previous section.In particular,the SUSY modi?cation of the universal terms consists of replacing the linear SM?3ln term by2ln,thus leading to a negative?ln e?ect,while the Yukawa term produces a substantial negative contribution due to the tanβparameter.

The Born part for q′=b or t is given by

dσBorn(gg→q′ˉq′)

4s [

u2+t2

4s2

](3.8)

and in a complete computation the SM QCD corrections will have to be added.

As one sees from eq.(3.6,3.7),as a”technical”consequence of the t,u channel diagrams dominance in the chosen con?guration,the SUSY electroweak and QCD e?ects concur at their(expectedly accurate)one-loop level to produce an overall negative e?ect that can be sizable,particularly for large tanβvalues where it could reach a relative twenty percent size,as we shall show in detail in the following Section.In this sense,and within the special scenario of large c.m.energies and”reasonably”light SUSY masses that we have?xed in this simpli?ed preliminary analysis,the chances of detecting a virtual SUSY e?ect in heavy quark production appear thus to be more promising for an experimental situation such that the considered initial gluon-gluon state gives(via its t and u channel diagrams)the dominant contributions to the cross section.From the available[16]luminosity pictures, we deduce that this request indicates the LHC experiments.Therefore,from now on we shall concentrate our investigation on this special machine,keeping in mind that for a di?erent scenario,whose analysis might be performed in a less simple way,the role of TEVATRON might be relevant,or dominant,as well.

As a?nal comment to this Section,we would like to remark the fact that the overall relative

identical with that which one one would ?nd,for the same heavy quark pair production in the identical c.m.energy and SUSY scenario,at a lepton collider (LC).Without writing additional explicit formulae,we can simply explain this statement with the observation that,in the relevant gluon-gluon initiated process,the surviving SUSY e?ect is of purely universal (i.e.process independent)kind and due to the heavy quark ?nal state,both for the electroweak and for the QCD SUSY components,the latter ones being entirely of vertex kind owing to the previously shown RG suppression.These contributions factorize in the same way and therefore produce the same relative SUSY e?ect for initial gluon-gluon and electron-positron state,even if the relative Standard Model corrections may be di?erent for the two cases e.g.when non universal angular dependent terms appear.The only (small)di?erences are due to the universal (non Yukawa)SUSY contribution (i.e.the ?ln (s/M 2)term)arising from the initial e +e ?state.

Our analysis of the simple partonic processes is thus completed.The next step is now that of considering to which amount the features that we have underlined will survive in the real process of production from a proton-proton state.This will be done in the forthcoming Section.

IV.CROSS SECTION FOR HEA VY QUARK PAIR PRODUCTION IN P P

COLLISIONS

We now consider proton-proton collisions with inclusive production of a pair of heavy quarks P P →q ′ˉq ′+......In this preliminary analysis we just want to show the role of the SUSY corrections on both quark-antiquark and gluon-gluon subprocesses.With this purpose we will concentrate our attention on the invariant mass distributions of ?nal b ˉb or t ˉt

quarks.Future works may consider other types of distributions (like p T distributions of the quarks or of their decay products)using the subprocess amplitudes that we have established in Sect.II and III,and the corresponding parton model kinematical tools.For a total c.m.squared energy S ,the q ′ˉq ′squared invariant mass (s )distribution is given by

dσ(P P →q ′ˉq ′+...)

cos θmax cos θmin d cos θ[ ij L ij (τ,cos θ)dσij →q ′ˉq ′S ,and (ij )represent all initial q ˉq pairs with q =u,d,s,c,b and the initial gg pairs,with the corresponding luminosities

L ij (τ,cos θ)=1x

)+j (x )i (τs

2lnχ,Y +1τ)}}ˉy min =?ˉy max (4.3)

where the maximal rapidity is Y=2,the quantityχis related to the scattering angle in the q′ˉq′c.m.

1+cosθ

χ=

4p2T,min

S=14TeV,a?xed SUSY mass scale M SUSY=350GeV and an angular cut corresponding to p T,min=10GeV.Concerning the parton distributions,

we must stress that in principle we should consider their evolution up to the desired √

energy scale

s=1TeV

the contribution of the gg subprocess represents about80%(88%)of the total Born cross

√

section for?nal bottom(top).At the smaller

1We used in this preliminary analysis the?xed values m t=173.8GeV,m b=4.25GeV, rather than(energy dependent)running values.In so doing,we ignored a higher order e?ect consistently with the philosophy of our paper.

In Fig.(7),we show the comparison between the e?ects in the Standard Model and those that we?nd in the MSSM at tanβ=40,a value that has the”advantage”of

providing a large correction due to the Yukawa terms.Indeed,it is precisely this kind of contribution that is responsible for the signi?cant enhancement of the e?ect compared

with the Standard Model case.The reason is the ampli?cation of the coe?cient of the m2t term by more than a factor2due to the replacement m2t→2m2t(1+cot2β)as well as the additional large correction tan2βintroduced by the analogous replacement

m2b→2m2b(1+tan2β).As a comment about the numerics we remark that in the Standard Model the Yukawa e?ect for?nal top is larger than in the case of?nal bottom by the factor(3m2t+m2b)/(m2t+m2b)?3explaining why the Standard Model full e?ect is larger for?nal top.In the MSSM at tanβ?40we already discussed the equivalence of the Yukawa e?ect for the?nal top or bottom.

Finally,in Fig.(8),we show the relative weights of the genuine SUSY contributions that are not present in the Standard Model.They are three,i.e.(i)the SUSY component of the QCD correction(we already mentioned the genuine Standard Model QCD correction and we simply remark that is shared by both the Standard Model and the MSSM), (ii)the SUSY gauge electroweak Sudakov(linear)logarithmic term,(iii)the additional tanβdependent Yukawa terms.The dominant e?ects are the Yukawa and the SUSY QCD correction,the?rst one being,as anticipated in the Introduction,the largest.In agreement with the previous Figure(7),the Yukawa part of the di?erence“MSSM-SM”is larger for?nal bottom(at tanβ=40).Indeed,as we remarked,we have MSSM(top)?MSSM(bottom)and SM(top)>SM(bottom)leading to MSSM-SM(top)

Figures(6-8)show the main result of our paper.One sees that the relative overall

SUSY e?ect could be large,varying from approximately ten percent to approximately twenty percent in the range tanβ=10?40.This e?ect is de?nitely larger than the corre-sponding SM one,as shown by Fig.(7).In particular,one notices that the enhancement is less due to the SUSY QCD contribution,and is mostly coming from the SUSY Yukawa term,which would be absent in the case of light quark production.For an experimen-tal and theoretical precision at the few percent level(i.e.summing statistics,detection e?ciencies and uncertainties in quark and gluon distributions),the presence of such a SUSY correction represents therefore,in our opinion,a feature of the process that cannot be ignored,and could provide a rather stringent test of the Supersymmetric model to be investigated.In this sense,the production of heavy quark pairs at LHC appears to us to be particularly interesting.

V.CONCLUSIONS

A number of realistic statements must be made when drawing some possible conclu-sions from this paper.Our analysis has undoubtedly been speci?c,since it has assumed a combination of events i.e.a previous discovery of Supersymmetric particles and a”rea-sonably light”nature of the SUSY scenario.In this particular case,we have shown that in the production of heavy quark pairs at c.m.energies in the one TeV range,where quite reasonably a one-loop logarithmic Sudakov expansion should provide an accurate descrip-tion of the virtual SUSY MSSM correction,the latter could reach values in the twenty percent range for large tanβand might be therefore detectable at proton colliders,in particular at the LHC which seems to us to be,for the speci?c c.m.energy con?guration that we have chosen,the more suitable machine.Of the relevant logarithmic expansion we have computed the leading(quadratic)and next to leading(linear)term,the SUSY genuine e?ect being simply of linear kind.We have performed this computation leaving undetermined a possible next-to-next-to leading term,in practice a constant one.In a complete treatment,the latter term should be computed or at least estimated.This is not trivial since in this quantity a large number of parameters of the supersymmetric model will generally appear,and several extra assumptions should be made concerning their values that are,we believe,beyond the realistic purposes of this?rst preliminary analysis2.With this premise,it seems to us that a relevant feature that emerges is that the relative size of the genuine SUSY correction could be large,de?nitely larger that in the SM case,mostly owing to the role of the Yukawa correction.

Another comment is related to the possibility that the SUSY scenario is not as”rea-sonably”light as we assumed.In the case for which the relevant masses are not huge, we feel,though,that the SUSY virtual e?ect,to be computed in a less simple way i.e. without logarithmic expansions,should still be numerically similar to the one that we computed,i.e.should not depend dramatically on the values of the SUSY masses of the process and should still be computable in a one loop approximation,and we will devote a future investigation to this special(negative)situation.

For what concerns a comparison with other similar work,we remark that our conclu-sions concerning a large virtual e?ect in the MSSM are in line(but with SUSY enhanced contributions)with those of an analysis of WW production in the Standard Model frame-work[18].It should also be recalled that,again within the Standard Model framework, the production of b pairs appears to be promising for the detection of virtual e?ects in precision measurements[4].In this sense,we believe to have shown that this conclusion could still be valid(and even more spectacular)for a more general class of?nal pairs,in a(hopefully valid)Supersymmetric picture.

REFERENCES

[1]see e.g.R.Str¨o hmer,Acta Physica Polonica B33(2002)3887;T.Kamon,hep-

ex/0301019,published in SUSY02,”Hamburg2002,Supersymmetry and Uni?cation of fundamental Interactions,vol.1,p.138.

[2]see e.g.D.P.Roy,hep-ph/0303106and F.E.Paige,hep-ph/0307342.

[3]The LEP Collaborations:ALEPH Coll,DELPHI Coll.,L3Coll.,OPAL Coll.,the

LEP Electroweak Working Group,the SLD Heavy Flavor Working Group,hep-ex/0212036.

[4]E.Maina,S.Moretti,M.R.Nolten and D.A.Ross,hep-ph/0307021,Phys.Lett.

B570,(2003)205.

[5]P.Nason,G.Ridol?,O.Schneider,G.F.Tartarelli and P.Vikas(conveners),in pro-

ceedings of the workshop on”Standard Model Physics(and more)at the LHC”, Geneva1999(p.231-304)and references therein.

[6]M.Beccaria,F.M.Renard and C.Verzegnassi,Phys.Rev.D64,073008(2001).

[7]M.Beccaria,M.Melles,F.M.Renard and C.Verzegnassi,Phys.Rev.D65,093007

(2002).

[8]M.Beccaria,F.M.Renard and C.Verzegnassi,Phys.Rev.D63,095010(2001);

Phys.Rev.D63,053013(2001);

[9]M.Beccaria,M.Melles, F.M.Renard,S.Trimarchi, C.Verzegnassi,

Int.Jour.Mod.Phys.A18,5069(2003).

[10]A.Castro,FERMILAB-CONF-02/213E(2002).

[11]M.Beccaria,F.M.Renard,S.Trimarchi,C.Verzegnassi,Phys.Rev.D68,035014

(2003).

[12]see e.g.R.K.Ellis,W.J.Stirling and B.R.Webber,”QCD and Colliders Physics”,

Cambridge University Press,eds.T.Ericson and https://www.doczj.com/doc/cf2859490.html,ndsho?(1996).

[13]M.Ciafaloni,P.Ciafaloni and https://www.doczj.com/doc/cf2859490.html,elli,Nucl.Phys.B589,359(2000).

[14]A.Denner,S.Pozzorini,Eur.Phys.J.C18,461(2001.

[15]M.Beccaria,F.M.Renard,C.Verzegnassi,Nucl.Phys.B663,394(2003).

[16]General information and updated numerical routines for parton distribution functions

can be found on the www site https://www.doczj.com/doc/cf2859490.html,/hepdata/.The set we used is described in A.D.Martin,R.G.Roberts,W.J.Stirling,R.S.Thorne,“MRST par-tons and uncertainties”,contribution to XI International Workshop on Deep Inelastic Scattering,St.Petersburg,23-27April2003,hep-ph/0307262.

[17]M.Beccaria,P.Ciafaloni,https://www.doczj.com/doc/cf2859490.html,elli,F.M.Renard,C.Verzegnassi,Phys.Rev.D

61,11301(2000).

[18]E.Accomando,A.R.Denner,S.Pozzorini,Phys.Rev.D65,073003(2002).

FIGURES

FIG.3.Diagrams for SUSY QCD corrections to the q ˉq →q ′ˉq ′annihilation amplitude (a,b,c,d),in which the internal solid lines are gluinos and the dashed lines are squarks,and diagram for gluon self-energy diagrams (e).

大学生毕业晚会主持词

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C：流火的六月，我们将带着恩师的叮咛，怀着必胜的信心，走向新的征程 D：绚烂的七月，我们将载着母校的祝愿，带着亲人的希望，向着新的征程扬帆起航A：老师们，同学们，欢送10级毕业生联欢晚会合：到此结束 A李：毕业，是一个沉重的动词；刘：毕业，是一个让人一生难忘的名词；李：毕业，是感动时流泪的形容词；刘：毕业，是当我们以后孤寂时候，带着微笑和遗憾去回想时的副词；李：毕业，是我们夜半梦醒，触碰不到而无限感伤的虚词。刘：若干年后，假如我们还能够想起那段时光，也许这不属于难忘，也不属于永远，而仅仅是一段记录了成长经历的回忆。李：尊敬的各位领导老师刘：亲爱的各位同学们合：大家晚上好！李：很荣幸和大家相聚在这激情如火的六月，在这充满忧伤的六月！刘：很高兴和大家相聚在“放心去飞，20年后再相聚—毕业晚会”现场！李：我是李扬刘：我是刘伟清李：今天晚会现场非常荣幸的邀请到院系的各位领导和老师们。刘：让我们首先欢迎…… 李：灿烂的星空曾经铭刻你我的笑容

湘艺版五年级音乐《长白山下的歌谣》教学设计

湘艺版五年级音乐《长白山下的歌谣》教学设计《长白山下的歌谣》教学设计教材版本：湘艺版音乐教材教学对象：五年级上期一、教学案例：（一）题：《长白山下的歌谣》音乐综合（二）教材版本：湘版新标实验教材（三）年级：五年级（四）教具准备：钢琴、AI、打击乐器、朝鲜族服饰、长鼓、金达莱花。（五）教学目标： ①、认知目标：认真听赏朝鲜民歌《道拉基》，学习三拍子节奏特点。 ②、能力目标：通过小组合作学习（设计身势节奏、用长鼓为歌曲伴奏、即兴歌舞等形式）培养学生的创新能力、合作能力，体验朝鲜族民歌的韵律。 ③、情感目标：通过感受性学习歌曲《金达莱花开朵朵红》，了解朝鲜族人民勤劳淳朴、团结互助、热情好客、能歌善舞的优良传统与民族风情。（六）设计思路：五十六个民族五十六枝花，生活在吉林省长白山脚下的

朝鲜族，其歌舞有着独特的节奏韵律。湘版新标实验教材五年级上册第八单元题为：《长白山下的歌谣》，它引起了我的研究兴趣。本单元的教育主题为：用民族音乐激发学生的爱国情感，实现多元文化的交流。即：通过音乐去感受民族文化，进而去了解民族文化；反之，通过文化，我们才可以去体验民族音乐，整体地去认识民族音乐。本时选用听赏《桔梗谣》和演唱歌曲《金达莱花开朵朵红》这两部分内容，教学设计的基本思路是：使学生通过多种形式听、唱“长白山下的歌谣”，深刻体验民族音乐“原生态”的美，以及其歌舞文化、思想内涵；在师生平等互动的学习氛围里，通过实践创作、对歌曲的再表现等形式，激发学生热爱民族音乐、热爱我们伟大祖国的情感。堂教学中我以“新程”为指导思想，对教学设计进行了一些新的尝试。以下结合自己教学实践中的堂教学个案，和大家共同评析与探讨。（七）教学过程 ᠄ 导入新过程：即“看风景”。、AI播放《大长今》影片，背景音乐:《大长今》的主题曲《希望》。（学生起立，跟随老师自由律动。）师：刚才同学们听到的旋律出自？

大学毕业晚会主持词四人

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不多，机会难得。下面请欣赏xxxx为大家带来的，钢琴四手连弹《军队进行曲》 6.幽幽云水意.漫漫古典情. 诗情画境的晕染为我们带来流动的娴静。请大家随着动人的舞蹈穿越书法的妙境，伴随优雅的琴韵体会超越喧嚣的古韵墨香。下面请欣赏xxx为您带来的xxxx 7.四年的岁月流光见证了你我在辽东学院的欢欣成长，相信由很多即将走出校园的同学都想倾诉衷肠，下面我们就请出来自05对外汉语的毕业生代表xxx听听她如何表达。 8.当你离开的时候，我送走你的只有沉默。当你离开我的时候，我绝不会把泪滴落。这是金达莱花的歌词大意，相信朝鲜族金达莱花的舞姿会像歌词一样优美，让人回味。下面请欣赏xxxx金达莱花。 9.是谁带来远古的呼唤，是谁留下千年的期盼，这首歌自打年初就开始被人重新无数次的翻唱，不过下面的歌曲，同样青藏高原的演唱，绝对会给您用实力带来不一样。由请xxxx 10.因为有爱，我们才牵手，因为有爱，我们才会风雨同舟。与身边爱自己的人共同牵手，一同遨游，幸福生活才能没有尽头。下面欣赏牵手。 11. 我对你的敬仰之情,如滔滔江水,连绵不绝;又如黄河之水,一发不可收拾;相信大家对电影《月光宝盒》中这一

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金达莱花谐音

na bu gei ma ya kiu 那不给妈呀久儿我 ga xi yi dai gei no 噶西带给路 ma lou xi bu yi mu lei du gei you li da 吗楼西不一木类度给有大 na bu gei ma ya kiu 那不给妈呀久儿我 ga xi yi dai gei no 噶西带给路 qiu kou lo a ni nu mu nu li you li na 求口咯啊你奴木奴里又里那 na dou na han bu ka qi 那都那汗不卡气 yi jian gu dai a ni ji 一见古带啊你几 ku dai pa la bu miao 苦带怕拉不秒 ca la wu dai ka 擦拉屋带卡 ku niao ti yi ka niao ji 苦鸟提一卡鸟几 ca la gu a gu mi no mu kou 擦拉古啊古米闹木口 cu wu xi wu s ka wo so 粗屋西屋丝卡我收 ku dai han bu ka gei 苦带汗不卡给 yi lu jiur gei you 一路酒给又 nei you mu nu lo 内有木奴咯 yi lu jiu gei you 一路就给又 na bu gei ma ya kiu 那不给妈呀久我 ga xi yi dai gei no 噶西带给路 ma lou xi bu yi mu lei du gei you li da 吗楼西不一木类度给有里大yang gou li ya sang jin dang nei gu wu 羊够里呀桑金当内古 a long da ma de xi gei lei gu li you li da 啊龙大吗的西给类古里有里大ka xi le gong long no yin ku kou qiu 卡西了工龙木因哭口求 na bu li qiu liu ma pu ma xi you so sou 那不里求留吗扑吗西有否搜 na bu gei ga ya piao ka xi dei you nu 那不给妈呀久我噶西带给路 qiu kou lo a ni nu mu nu li you li na 求口咯啊你奴木奴里又里那 nei ga dou na ba leng dei you 内噶都那吧冷给又 ku dai lu man du la wu 苦带路满度啦舞 ku dan ku miao sa la han gei ji 苦但苦秒撒拉汗给几 na bu gei ma ya kiu 那不给妈呀久我 ga xi yi dai gei no 噶西带给路 ma lou xi bu yi mu lei du gei you li da 吗楼西不一木类度给有里大 yang gou li ya sang jin dang nei gu wu 羊够里呀桑金当内古 a long da ma de xi gei lei gu li you li da 啊龙大吗的西给类古里有里大ka xi le gong long no yin ku kou qiu 卡西了工龙木因哭口求 na bu li qiu liu ma pu ma xi you so sou 那不里求留吗扑吗西有否搜na bu gei ga ya piao ka xi dei you nu 那不给妈呀久我噶西带给路 qiu kou lo a ni nu mu nu li you li na 求口咯啊你奴木奴里又里那 na bu gei ga ya piao ka xi dei you nu 那不给妈呀久我噶西带给路 qiu kou lo a ni nu mu nu li you li na 求口咯啊你奴木奴里又里那

主持词 2020年大学毕业晚会主持词

xx年大学毕业晚会主持词 b：让我们静静享受一下挑战，在日复一日与时间的赛跑中，你会变得更加坚强，更加神采奕奕!又一个青春之旅从今晚启航，又一个光阴的故事在今晚讲述 c：亲爱的同窗，不要带着离别的愁绪，因为明天又是一个新的起点，因为我们相信再次相逢，我们还是一首动人的歌!d：很高兴今天能有这个机会同大家相聚一堂，共叙离别。就让今天铭刻在我们心间，让母校留住我们的风采! a：今天，我们也非常荣幸的请到了 b：下面让我们用热烈的掌声有请上台讲话结束语a：欢快的舞蹈表达不尽我们对母校的敬意 b：热情的赞歌唱不尽我们对母校的一腔深情 c：流火的六月，我们将带着恩师的叮咛，怀着必胜的信心，走向新的征程 d：绚烂的七月，我们将载着母校的祝愿，带着亲人的希望，向着新的征程扬帆起航 a：老师们，同学们，欢送10级毕业生联欢晚会合：到此结束a李：毕业，是一个沉重的动词; 刘：毕业，是一个让人一生难忘的名词; 李：毕业，是感动时流泪的形容词; 刘：毕业，是当我们以后孤寂时候，带着微笑和遗憾去回想时的副词;

李：毕业，是我们夜半梦醒，触碰不到而无限感伤的虚词。刘：若干年后，假如我们还能够想起那段时光，也许这不属于难忘，也不属于永远，而仅仅是一段记录了成长经历的回忆。李：尊敬的各位领导老师刘：亲爱的各位同学们合：大家晚上好! 李：很荣幸和大家相聚在这激情如火的六月，在这充满忧伤的六月! 刘：很高兴和大家相聚在放心去飞，20年后再相聚毕业晚会现场! 李：我是李扬刘：我是刘伟清李：今天晚会现场非常荣幸的邀请到院系的各位领导和老师们。刘：让我们首先欢迎李：灿烂的星空曾经铭刻你我的笑容刘：美丽的海岸曾经珍藏你我的背影。李：连绵起伏的山川，像一双腾飞的翅膀支撑起我们坚韧不屈的信念，刘：沸腾的黄海血脉，像千万奔涌的旋律连绵成我们亘古不灭的传说。李：在这个光荣同梦想交融的时刻，让我们共同祈祷合：环保的明天更美好!

毕业生晚会主持稿

毕业生晚会主持稿毕业生晚会主持稿(一) A：青春是一曲荡气回肠的歌，三年前我们怀着彩色梦想走进了鄂大，三年中我们有过欢笑，流过泪水，经历磨炼，得到成长：三年后的今天，我们在这里重温青春过往，因为明天就将各奔天涯。也正因为此，今夜，我们承载了太多的祝福与惦念，寄托了太多的关怀与企盼。 C：今晚，让我们再一次重温，那些感动过我们的人和事：灯火通明的教学楼里用功的身影，篮球场上捍卫集体尊严的男儿霸气，满是欢声笑语的宿舍边不着边际的闲谈 D：又一个三年轮回之后，在同样微凉的夏夜，你是否会记起校园里的梧桐树，你是否会记起日记本里的书签，那些五彩缤纷的日子? A：无数个三年之后，你们的思念是否会有增无减?在你成长的岁月里，在你闯荡社会的每一天，是否会有那么几个瞬间让你渴望回到过去：让我们静静享受一下挑战，在日复一日与时间的赛跑中，你会变得更加坚强，更加神采奕奕!又一个青春之旅从今晚启航，又一个光阴的故事在今晚讲述 C：亲爱的同窗，不要带着离别的愁绪，因为明天又是一个新的起点，因为我们相信再次相逢，我们还是一首动人的歌!D：很

高兴今天能有这个机会同大家相聚一堂，共叙离别。就让今天铭刻在我们心间，让母校留住我们的风采! A：今天，我们也非常荣幸的请到了：下面让我们用热烈的掌声有请上台讲话结束语A：欢快的舞蹈表达不尽我们对母校的敬意：热情的赞歌唱不尽我们对母校的一腔深情 C：流火的六月，我们将带着恩师的叮咛，怀着必胜的信心，走向新的征程 D：绚烂的七月，我们将载着母校的祝愿，带着亲人的希望，向着新的征程扬帆起航 A：老师们，同学们，欢送10级毕业生联欢晚会合：到此结束 A李：毕业，是一个沉重的动词; 刘：毕业，是一个让人一生难忘的名词; 李：毕业，是感动时流泪的形容词; 刘：毕业，是当我们以后孤寂时候，带着微笑和遗憾去回想时的副词; 李：毕业，是我们夜半梦醒，触碰不到而无限感伤的虚词。刘：若干年后，假如我们还能够想起那段时光，也许这不属于难忘，也不属于永远，而仅仅是一段记录了成长经历的回忆。李：尊敬的各位领导老师刘：亲爱的各位同学们

大学生精彩毕业晚会主持词

大学生精彩毕业晚会主持词大学生精彩毕业晚会主持词 A：六月、江畔的微风情深意暖，校园涌动的花海流溢飘香。 B：六月、想起毕业带来的奔忙，满怀即将失去的无限感伤。 C：六月、拾起曾经蕴藏的过往，体味相伴四年的欢欣成长。 D：六月、让你我懂得了珍惜，珍惜在校的每一段岁月流光。 A：毕业，是一沉重的动词，行动里带着眷恋与不舍。 B：毕业，是一难忘的名词，话语里带着心酸与苦涩。 C：毕业，是一流泪的形容词，不可或缺但又不能推辞。 D：毕业，是个遗憾的副词，历练成长却又让生活充实。 A：四年前，大家相遇相知，温暖胸膛、怀揣梦想。 B：四年里，大家共同努力，激越青春、欢乐成长。 C：四年后，即将天各一方，各自打造梦想的天堂。 D：朋友们，不要让泪水打湿容颜，火热激情即将绽放当晚，让我们的心于空中翱翔，在青春的蓬勃下生长，在岁月流光中温暖启航。 A：下面我宣布，20XX年师范学院青春启航文化节之毕业生晚会正式开始。 1.节奏引领时尚，余音环绕广场，新鲜的韵律，高难度的声响，一样为您缔造不一样的完美想象，下面请欣赏来自XX音乐班的xxx为您带来的《》相信会给您带来意外的惊喜。

2.铃声清脆鼓铿锵，天山铃舞尽展情，来自天山的自然是蝶飞花影动，美丽各不同，那就让我们停下脚步，一饱眼福，欣赏由xxx为我们带来的舞蹈《天山铃舞》 3. 军中有歌，歌才动情，军旅里飞来一只熟悉的百灵，不错下面就由请xxx为大家献上一首耳熟能详的老歌，《军中飞来一只百灵》 4.炫酷才叫时尚，八零后心之向往，相信大家都一样，需要个性张扬。今天我们特意请来了城市建设学院的武状元优秀团队，为大家献上一段充满活力的XXX，感谢他们的到来，大家掌声欢迎! 5.相信大家都看过一部曾经风靡一时的电影，那是周杰伦曾经推出的一部年度巨献《不能说的秘密》.里面的四手联弹一定给大家留下了不可磨灭的深刻印象，旋律依旧在脑中回响。不过经典一样可以复制，精彩一样能够粘贴，下面给大家带来的这个惊喜，可谓是非常具有特色，一样是所见不多，机会难得。下面请欣赏xxxx为大家带来的，钢琴四手连弹《军队进行曲》 6.幽幽云水意.漫漫古典情. 诗情画境的晕染为我们带来流动的娴静。请大家随着动人的舞蹈穿越书法的妙境，伴随优雅的琴韵体会超越喧嚣的古韵墨香。下面请欣赏xxx为您带来的xxxx 7.四年的岁月流光见证了你我在XX学院的欢欣成长，相信由很多即将走出校园的`同学都想倾诉衷肠，下面我们就请出来自05对外汉语的毕业生代表xxx听听她如何表达。

校园艺术节主持词开场白

校园艺术节主持词开场白（一）男：尊敬的各位领导、各位来宾。女：亲爱的老师们、同学们。合：大家好！男：聆听十月的讯息，秋风吹拂大地；女：走进十月的校园，我们充满活力！男：今天，我们相聚这儿，绽放灿烂的笑容；凝聚我们的勇气；女：今天，我们相聚这儿，放飞我们的希望，追求我们的梦想！男：校园的艺术是知识的一种新的升华，校园的生活是多彩的音乐的合奏。女：校园艺术节是师生展示各自文艺风采、凸显个性魅力的一个最佳舞台。合：xx中学第x届校园艺术节开幕式现在开始！（鸣礼炮）男：下面进行升旗仪式，请仪仗队入场。女：请全体起立，升国旗、奏国歌！男：请大家入座。今天来到我们会场的领导有：xx、xx、xx…… 女：让我们用热烈的掌声对他们的到来表示欢迎！男：另外许多家长代表也来到了我们的会场，一个成功的学生背后总有辛勤付出的家长，您辛苦了！女：让我们用热烈的掌声对他们表示感谢！男：回首我们走过的这一个学年，经过全校师生上下一心、卓有成效的努力，我校各项工作都取得了骄人的成绩：校容校貌焕然一新，常规管理扎实有效，教学质量跃上新高。

女：成绩已然过去，面对未来，我们信心百倍。下面有请x校长讲话。（鼓掌感谢x校长的精彩致辞）环节一：教师合唱《走进新时代》、《团结就是力量》男：我们xx人是这样的热情奔放！女：我们xx人是这样的团结激昂！男：我们的手牵在一起，就是战胜困难的力量！女：我们的心连在一起，就是坚不可摧的铜壁铁墙！男：让我们与优美同行，与高雅同行，与时代同行女：请欣赏教师合唱《走进新时代》和《团结就是力量》。指挥：xx 领唱：xx 环节二：舞蹈《开门红》女：扬起你欢乐的嘴角，带上你的好心情，在这个特别的日子里跟我们一起感受这花样年华。

毕业典礼晚会主持词

毕业典礼晚会主持词X 花开花落，又是一年毕业季，我们毕业典礼就要开始举办，下面是搜集整理的毕业典礼晚会主持词，欢迎阅读。更多资讯请继续关注毕业典礼栏目! 毕业典礼晚会主持词(一) A：青春是一曲荡气回肠的歌，三年前我们怀着彩色梦想走进了鄂大，三年中我们有过欢笑，流过泪水，经历磨炼，得到成长 B：三年后的今天，我们在这里重温青春过往，因为明天就将各奔天涯。也正因为此，今夜，我们承载了太多的祝福与惦念，寄托了太多的关怀与企盼。 C：今晚，让我们再一次重温，那些感动过我们的人和事：灯火通明的教学楼里用功的身影，篮球场上捍卫集体尊严的男儿霸气，满是欢声笑语的宿舍边不着边际的闲谈…… D：又一个三年轮回之后，在同样微凉的夏夜，你是否会记起校园里的梧桐树，你是否会记起日记本里的书签，那些五彩缤纷的日子? A：无数个三年之后，你们的思念是否会有增无减?在你成长的岁月里，在你闯荡社会的每一天，是否会有那么几个瞬间让你渴望回到过去 B：让我们静静享受一下挑战，在日复一日与时间的赛跑中，你会变得更加坚强，更加神采奕奕!又一个青春之旅从今晚启航，又一个光阴的故事在今晚讲述 C：亲爱的同窗，不要带着离别的愁绪，因为明天又是一个新的起点，因为我们相信再次相逢，我们还是一首动人的歌!D：很高兴今天能有这个机会同大家相聚一堂，共叙离别。就让今天铭刻在我们心间，让母校留住我们的风采! A：今天，我们也非常荣幸的请到了…… B：下面让我们用热烈的掌声有请……上台讲话

结束语 A：欢快的舞蹈表达不尽我们对母校的敬意 B：热情的赞歌唱不尽我们对母校的一腔深情 C：流火的六月，我们将带着恩师的叮咛，怀着必胜的信心，走向新的征程 D：绚烂的七月，我们将载着母校的祝愿，带着亲人的希望，向着新的征程扬帆起航 A：老师们，同学们，欢送10级毕业生联欢晚会合：到此结束 A李：毕业，是一个沉重的动词; 刘：毕业，是一个让人一生难忘的名词; 李：毕业，是感动时流泪的形容词; 刘：毕业，是当我们以后孤寂时候，带着微笑和遗憾去回想时的副词; 李：毕业，是我们夜半梦醒，触碰不到而无限感伤的虚词。刘：若干年后，假如我们还能够想起那段时光，也许这不属于难忘，也不属于永远，而仅仅是一段记录了成长经历的回忆。李：尊敬的各位领导老师刘：亲爱的各位同学们合：大家晚上好! 李：很荣幸和大家相聚在这激情如火的六月，在这充满忧伤的六月! 刘：很高兴和大家相聚在“放心去飞，20年后再相聚—毕业晚会”现场! 李：我是李扬

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