Signals for Majorana neutrinos in a $gamma gamma$ collider
a r X i v :h e p -p h /0211355v 1 22 N o v 2002Signals for Majorana neutrinos in a γγcollider
J.Peressutti and O.A.Sampayo
Departamento de F′?sica,Universidad Nacional de Mar del Plata
Funes 3350,(7600)Mar del Plata,Argentina
Abstract
We study the possibilities to detect Majorana neutrinos in γγcolliders for di?erent center of mass energies.We study the W ±W ±l ?j l ?k (l j ≡e,μ,τ)?nal states which are,due to leptonic number violation,a clear signature for intermediate Majorana neutrino contribution.Such a signal (?nal dileptons of the same sign)is not possible if the heavy neutrinos are Dirac particles.We present our results for the total cross-section as a function of the neutrino mass and the center of mass energies.
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I.INTRODUCTION
Massive neutrinos can come in two di?erent types:as Dirac or Majorana particles. Dirac fermions have distinct particles and antiparticle degrees of freedom while Majorana
fermions make no such distinction and have half as many degrees of freedom[1].In this conditions fermions with conserved charges(color,electric charged,lepton number,...)must
be of Dirac type,while fermions without conserved charges may be of either type.New
neutrinos could have large masses and be of either type.If there are heavy neutrinos(N), then the present and future experiments o?er the possibility of establishing their nature.
The production of Majorana neutrinos via e+e?,e?γ,γγand hadronic collision have been
extensively investigated in the past[2,3,4,5,6,7,8,9].In this work we study the possibility of theγγlinear collider to produce clear signatures for Majorana neutrinos.The photon linear
collider[10]may be the best alternative to the electron positron colliders.In this paper we discuss the possible detection of Majorana neutrinos in the reactionsγγ→W±W±l?j l?k
(l j≡e,μ,τ)where the real gamma beam are obtained by Comptom backscattering of laser photons o?the linear electron beam.In this process most of the photons are produced at the high energy regions.For the cross section calculation we have used the helicity formalism
[11,12],considering the complete set of Feynman diagrams show in Fig.1.The phase space
integration was done taking account that the intermediate neutrinos can be either on shell
or o?shell.In this point the present work di?er of previous calculation[9]where the √
restriction M N>
s the new heavy neutrino is more likely to be?rst discovered via
single production in e+e?→νN.However theγγcollider have some facilities that make it suitable to search Majorana neutrinos and study their interactions.In particular aγγcollider o?er the possibility to control the helicity of the colliding photons controlling the helicity of the Laser https://www.sodocs.net/doc/054439535.html,ing these polarized high energy photon beams we have the possibility to study in detail the interactions of Majorana neutrinos and reject possible backgrounds.Due the large CM energies of these colliders we have considered that the mass of the?nal lepton vanishes.
For the couplings of the Majorana neutrinos we follow Ref[6]starting with rather general
lagrangian densities for the interaction of N with W and light leptons l j(e,μ,τ):
L NW l=?3 j=1gB(j)L2ˉl jγμP L NW?μ+h.c.(1)
The heavy Majorana neutrino couples to the three?avors lepton with couplings proportional to B(j)L,where j labels the family.This(B(j)L)2constant are,in notation of[13],the sin square of the mixing angle between light and heavy neutrinos((Sνe L)2,(SνμL)2,(SντL)2).The constant g is the standard SU(2)L gauge coupling.
This B(j)L parameters will a?ect the?nal results via the combinations
H i=|B(i)L|2and H=3 j=1|B(j)L|2(2)
The?nal leptons can be either of e?,μ?orτ?because this is allowed by the interaction lagrangian(eq.1).All these possible?nal states are a clear signal for intermediary Majorana neutrino and then we sum the cross section over the?avors of the?nal lepton.This sum depend of H,H1,H2and H3in the numerator of the total cross section.In the other hand this cross-section also depends on H through the total widthΓN→all in the Majorana neutrino propagator.This last dependence is relevant when the Majorana neutrino is on-shell.We use the Breit-Wigner propagator for the Majorana neutrino N for di?erent values of the mass M N.The total widthΓN→all of N was determined at tree level considering the dominant decay modes N→W±l?j:
g2H
ΓN→all=
2 factor is included to avoid double counting of the two W and another1
s and M N.The H dependence is complicate due to the Majorana
neutrino propagator.We have founded that the most important contribution to|ˉM|2
√coming from the couplings is proportional to H2.However in the M W s?M W region(Reg.II),where the Majorana neutrino is o?-shell,the total cross-section is approximately proportional to H2.The behaviour in Reg.I is easy to realize if we make the so-called peaking approximation,in which the Breit-Wigner shape of the Majorana neutrino propagator is replaced by a delta function.In this region the H2dependence in the numerator is canceled by the H factor in the total width.Considering only the relevant factors in the cross section,we have σ= jσj～···H21 (q2?M2N)2+M2NΓ2N···→ π s(the center of mass energie of theγγsubprocess)and M N.The numerical Monte Carlo integration was done using the FORTRAN subroutine RAMBO[16].The Fig.2show the M N dependence of the unpolarized cross-section σat?xed √ s=500GeV. Moreover,partial results were also checked using the CalcHep program[17].In Fig.3we show the √ dτ σγγ→W±W±l?l?(τs)(8) The di?erential luminosity dLγγ/dτis de?ned as usual in terms of photons structure functions of electrons(f(x))beam: dLγγ x max dx x )(9) whereτ= s/s. √ and x is the fraction of the parent electron’s energies carried by the photons.The maximum possible value for x is x max=ξ m e ;(11) where E0andω0are the incident electron and laser light energies.To avoid unwanted e+e?pair production from the collitions between the incident and back-scattered photons, we should no choose too largeω0.This fact constraint the maximum value forξto be ξ=2(1+ √ x a dx b f(x a)f(x b) σ(x a x b s)(12) where x min a =τmin/x max. To illustrate the possible impact of this process in the discovery of Majorana neutrinos we show in Fig4the number of events as a function of √ s for M N=300GeV.The horizontal line represent the maximum possible value for H. Summarizing,we calculate the cross-section for the processγγ→W±W±l?j l?k where l1,l2and l3are light leptons(e,μ,τ)respectively.We show the total unpolarized cross-section for the subprocessγγfor di?erent values of √ s considering the real gamma beam is obtained by the Comptom backscattering of laser photons o?the linear electron beam. Acknowledgements We thank CONICET(Argentina)and Universidad Nacional de Mar del Plata(Ar-gentina)for their?nancial supports. REFERENCES [1]B.Kayser,F.Gibrat-debu,and F.Perrier,The Physics of Massive Neutrinos(World Sci- enti?c,Singapore,1989) [2]Ernest Ma and James Pantaleone,Phys.Rev.D40,2172(1989) [3]A.Datta,M.Guchait and A.Pilaftsis,Phys.Rev.D50,3195(1994) [4]J.Gluza and M.Zralek,Phys.Rev.D51,4707(1995) [5]Axel Hoefer and L.M.Sehgal,Phys.Rev D54,1944(1996) [6]G.Cvetic,C.S.Kim and C.W.Kim,Phys.Rev.Lett.82,1999. [7]F.M.L.Almeida Jr,Y.A.Coutinho,J.A.Martins Simoes and M.A.B.do Vale,hep- ph/0002024 [8]J.Peressutti,A.O.Sampayo and J.I.Aranda,Phys.Rev.D64,073007(2001). [9]G.Belanger,F.Bojudema,D.London and H.Nadeau.Phys.Rev.D53,6292(1996). [10]T.Ohgaki,T.Takahashi and I.Watanabe,Phys.Rev.D561723(1997). [11]P.De Causmaecker,R.Gastmans,W.Troost and T.T.Wu,Phys.Lett.B105,(1981) 215;P.De Causmaecker,R.Gastmans,W.Troost and T.T.Wu,Nucl.Phys.B206, (1982)53;F.A.Berends,R.Kleiss,P.De Causmaecker,R.Gastmans,W.Troost and T. T.Wu,Nucl.Phys.B206,(1982)61;D.Dankaert,P.De Causmaecker,R.Gastmans,W. Troots and T.T.Wu,Phys.Lett.B114,(1982)203;F.A.Berends,P.De Causmaecker, R.Gastmans,R.Kleiss,W.Troost and T.T.Wu,Nucl.Phys.B239,(1984)382;F.A. Berends,P.De Causmaecker,R.Gastmans,R.Kleiss,W.Troost and T.T.Wu,Nucl. Phys.B239,(1984)395;F.A.Berends,P.De Causmaecker,R.Gastmans,R.Kleiss,W. Troost and T.T.Wu,Nucl.Phys.B264,(1986)234;F.A.Berends,P.De Causmaecker, R.Gastmans,R.Kleiss,W.Troost and T.T.Wu,Nucl.Phys.B264,(1986)265. [12]R.Kleiss and W.J.Stirling,Nucl.Phys.B262(1985)235-262. [13]E.Nardi,E.Roulet,D.Tomassini,Phys.Lett.B344,225(1995). [14]https://www.sodocs.net/doc/054439535.html,ngacker and D.London,Phys.Rev.D38,886(1988). [15]A.Balysh et al,Phys.Lett.B356,450(1995). [16]R.Kleiss and W.J.Stirling,https://www.sodocs.net/doc/054439535.html,mun.40;359,1986 [17]A.Pukhov et al,”CompHEP-a package for evaluation of Feynman diagrams and inte- gration over multi-particle phase space.”,Preprint INP MSU98-41/542,hep-ph/9908288 [18]Ilya F.Ginzburg hep-ph/9907549 Figure Captions Figure1:Feynman graph contributing to the amplitude of theγγ→W+W+l?l?process. Figure2:Unpolarized cross-section( σ)for theγγ-subprocess as a function of the Majorana √ neutrino masses(M N)for di?erent center of mass energies( s=500GeV,a plot ofσ(γγ→l?NW±)Br(N→l?W±)(Dot-Dash). Figure3:Unpolarized cross section( σ)for theγγ-subprocess as a function of the center √ of mass energies( s for M N=300GeV. Figure5:Contour Plot for the number of events(1000,500,100,30,1)as a function of √ 100200300400500 10-8 10-7 10-6 10-510-4 10-3 10-2 10-1 ^^^^s=200 GeV s=300 GeV s=500 GeV σ [p b ]m N [GeV] 300350400450500 10-610-5 10-4 10-310-2^^ M N =500 GeV M N =300 GeV M N =200 GeV σ [ p b ] s [GeV] 2004006008001000 100 101 102 103 Fig.4 M N =300 GeV N u m b e r o f E v e n t s s [GeV] 200300400500600700800900100010-5 10-410-3 10-2 10-1100 H M N = 300 GeV 130 100 500 1000s [GeV] (一) 假定你是红星中学初三学生李华。你的美国朋友Jim在给你的邮件中提到他对中国新近出现的一种共享单车“mobike”很感兴趣，并请你做个简要介绍。请你给Jim回信，内容包括： 1. 这种单车的使用方法(如：APP查看车辆、扫码开锁等); 2. 这种单车的优势; 3. 你对这种单车的看法。 注意：1. 词数不少于80; 2. 开头和结尾已给出，不计入总词数。 提示词：智能手机smartphone, 二维码the QR code 参考范文 Dear Jim, I’m writing to tell you more about the new form of sharing bike mobike mentioned in your latest letter. It’s very convenient to use if you have a smartphone. What you do is find a nearest mobikethrough the APP, scan the QR code on the bike, and enjoy your trip. Compared to other forms of sharing bike, the greatest advantage of mobike is that you can easily find one and never worry about where to park it. It is becoming a new trend as a means of transportation, which relieves the traffic pressure and does good to the environment as well. Hope to ride a mobike with you in China. Yours, Li Hua (二) 最近很多大城市都投放了共享单车(shared bikes)，比如摩拜单车(Mobike)、Ofo共享单车等。由于它们方便停放，骑车也能起到锻炼身体的作用，作为代步工具很受大家欢迎。但是，各地也出现了很多毁车现象，比如刮掉车上的二维码(QR code)、上私锁等。 你对这种现象怎么看?你对共享单车公司有什么建议吗?写一篇符合逻辑的英语短文，80词左右。 参考词汇：bike-sharing companies 共享单车公司，Mobike 和Ofo 是两家共享单车公司，convenience 方便，register登记 参考范文 The shared bikes like Mobike and Ofo bring great convenience to people. You needn’t lock them by simply using your smart phone. They can take you where the subway and bus don’t go. And they can be left anywhere in public for the next user. However, bad things happen. Some people damage the QR code on the bike, or use their own lock, which causes trouble to other users. In my opinion, it’s difficult to turn these people’s ideas in a short time. Therefore, bike-sharing companies like Mobike and Ofo need to do something. For example, those who damage the bike should pay for their actions. Also, because people use their real name toregister as a user, it’s a good way to connect to one’s personal credit. In the end, what I want to say is to take good care of public services. (三) 共享单车(bicycle sharing)已成为时下最热的话题之一，请你就这一话题写一篇短文。内容须包括三方面：1. 共享单车蓬勃发展，成为社会热潮;2. 共享单车带来便利，但也存在问题;3. 我对解决问题的建议。 参考范文 Bicycle Sharing With the development of technology, bicycle sharing comes into people's lives. It becomes more and more popular and much news reported it. At the same time, we should see that there are some problems caused by bicycle sharing. On one side, bicycle sharing makes it very convenient of people traveling. You can find a bicycle anywhere at any time when you want to go out for a cycling, and the price of one trip is very low. It can save time for people. On the other side, its management is not perfect. Even kids can open the lock and ride the bicycle, there is no doubt that such behavior is very dangerous. 介绍北京的英语作文(2) AsBeijinghasbeenconfirmedhomecityofOlympics2008,the spiritofgreenOlympics,scientificOlympicsandhumanizedOlymp icwillsurelybringmoreandmorechangestoBeijing,promotethed evelopmentofsportsandOlympicsinChinaaswellasintheworld,a ndstrengthenthefriendlycommunicationsbetweenChineseandf oreignpeople. 篇六：Beijing BeijingisthecapitalofPeoplesRepublicofChinaandthenation scentreforpolitics,economyandculture.Itenjoysalongandrichhis tory.Therearenumerousheritagesitesandwonderfulexamplesof ancientarchitecture,suchastheworld-famousGreatWall,theTem pleofHeavenandtheForbiddenCity. Besidessightseeingplaces,therearemanydeliciousfoodsuch asPekingducksandBeijingsnacks.Beijingisreallyagoodplacetotr avel. 篇七：Beijing AsthecaptainofChina，Beijinghasbeenthemostpopularcityofchina。SomoreandmorepeoplewanttovisitBeijing. The way 的用法 Ⅰ常见用法： 1)the way+ that 2)the way + in which（最为正式的用法） 3)the way + 省略（最为自然的用法） 举例：I like the way in which he talks. I like the way that he talks. I like the way he talks. Ⅱ习惯用法： 在当代美国英语中，the way用作为副词的对格，“the way+ 从句”实际上相当于一个状语从句来修饰整个句子。 1)The way =as I am talking to you just the way I’d talk to my own child. He did not do it the way his friends did. Most fruits are naturally sweet and we can eat them just the way they are—all we have to do is to clean and peel them. 2）The way= according to the way/ judging from the way The way you answer the question, you are an excellent student. The way most people look at you, you’d think trash man is a monster. 3）The way =how/ how much No one can imagine the way he missed her. 4）The way =because AN EXCITING JOB I have the greatest job in the world. I travel to unusual places and work alongside people from all over the world. Sometimes working outdoors, sometimes in an office, sometimes using scientific equipment and sometimes meeting local people and tourists, I am never bored. Although my job is occasionally dangerous, I don't mind because danger excites me and makes me feel alive. However, the most important thing about my job is that I help protect ordinary people from one of the most powerful forces on earth - the volcano. I was appointed as a volcanologist working for the Hawaiian V olcano Observatory (HVO) twenty years ago. My job is collecting information for a database about Mount Kilauea, which is one of the most active volcanoes in Hawaii. Having collected and evaluated the information, I help other scientists to predict where lava from the volcano will flow next and how fast. Our work has saved many lives because people in the path of the lava can be warned to leave their houses. Unfortunately, we cannot move their homes out of the way, and many houses have been covered with lava or burned to the ground. When boiling rock erupts from a volcano and crashes back to earth, it causes less damage than you might imagine. This is because no one lives near the top of Mount Kilauea, where the rocks fall. The lava that flows slowly like a wave down the mountain causes far more damage because it 【摘要】黄自先生是我国杰出的音乐家，他以艺术歌曲的创作最为代表。而黄自先生特别强调了钢琴伴奏对于艺术歌曲组成的重要性。本文是以黄自先生创作的具有爱国主义和人道主义的艺术歌曲《天伦歌》为研究对象，通过对作品分析，归纳钢琴伴奏的弹奏方法与特点，并总结黄自先生的艺术成就与贡献。 【关键词】艺术歌曲；和声；伴奏织体；弹奏技巧 一、黄自艺术歌曲《天伦歌》的分析 （一）《天伦歌》的人文及创作背景。黄自的艺术歌曲《天伦歌》是一首具有教育意义和人道主义精神的作品。同时，它也具有民族性的特点。这首作品是根据联华公司的影片《天伦》而创作的主题曲，也是我国近代音乐史上第一首为电影谱写的艺术歌曲。作品创作于我国政治动荡、经济不稳定的30年代，这个时期，这种文化思潮冲击着我国各个领域，连音乐艺术领域也未幸免――以《毛毛雨》为代表的黄色歌曲流传广泛，对人民大众，尤其是青少年的不良影响极其深刻，黄自为此担忧，创作了大量艺术修养和文化水平较高的艺术歌曲。《天伦歌》就是在这样的历史背景下创作的，作品以孤儿失去亲人的苦痛为起点，发展到人民的发愤图强，最后升华到博爱、奋起的民族志向，对青少年的爱国主义教育有着重要的影响。 （二）《天伦歌》曲式与和声。《天伦歌》是并列三部曲式，为a+b+c，最后扩充并达到全曲的高潮。作品中引子和coda所使用的音乐材料相同，前后呼应，合头合尾。这首艺术歌曲结构规整，乐句进行的较为清晰，所使用的节拍韵律符合歌词的特点，如三连音紧密连接，为突出歌词中号召的力量等。 和声上，充分体现了中西方作曲技法融合的创作特性。使用了很多七和弦。其中，一部分是西方的和声，一部分是将我国传统的五声调式中的五个音纵向的结合，构成五声性和弦。与前两首作品相比，《天伦歌》的民族性因素增强，这也与它本身的歌词内容和要弘扬的爱国主义精神相对应。 （三）《天伦歌》的伴奏织体分析。《天伦歌》的前奏使用了a段进唱的旋律发展而来的，具有五声调性特点，增添了民族性的色彩。在作品的第10小节转调入近关系调，调性的转换使歌曲增添抒情的情绪。这时的伴奏加强和弦力度，采用切分节奏，节拍重音突出，与a段形成强弱的明显对比，突出悲壮情绪。 c段的伴奏采用进行曲的风格，右手以和弦为主，表现铿锵有力的进行。右手为上行进行，把全曲推向最高潮。左手仍以柱式和弦为主，保持节奏稳定。在作品的扩展乐段，左手的节拍低音上行与右手的八度和弦与音程对应，推动音乐朝向宏伟、壮丽的方向进行。coda 处，与引子材料相同，首尾呼应。 二、《天伦歌》实践研究 《天伦歌》是具有很强民族性因素的作品。所谓民族性，体现在所使用的五声性和声、传统歌词韵律以及歌曲段落发展等方面上。 作品的整个发展过程可以用伤感――悲壮――兴奋――宏达四个过程来表述。在钢琴伴奏弹奏的时候，要以演唱者的歌唱状态为中心，选择合适的伴奏音量、音色和音质来配合，做到对演唱者的演唱同步，并起到连接、补充、修饰等辅助作用。 作品分为三段，即a+b+c+扩充段落。第一段以五声音阶的进行为主，表现儿童失去父母的悲伤和痛苦，前奏进入时要弹奏的使用稍凄楚的音色，左手低音重复进行，在弹奏完第一个低音后，要迅速的找到下一个跨音区的音符；右手弹奏的要有棱角，在前奏结束的时候第四小节的t方向的延音处，要给演唱者留有准备。演唱者进入后，左手整体的踏板使用的要连贯。随着作品发展，伴奏与旋律声部出现轮唱的形式，要弹奏的流动性强，稍突出一些。后以mf力度出现的具有转调性质的琶音奏法，要弹奏的如流水般连贯。在重复段落，即“小 [标签:标题] 篇一：关于汽车的英语作文 好的 Nowadays, with the rapid improvement of people’s living standards, cars have become an indispensable part of people's lives,so that more and more people have a car of their own, especially in cities. It brings some benefits for us but also causes many problems at the same time. For one thing,there’s no doubt that cars provide much convenience for people to go where they want to quickly and easily. Especially on weekday,driving a car can save a lot of time for us to go to work.When some places are too far away from our home, driving our own car is also convenient, we can go wherever we want. However,for another, too many cars will lead to the pressure of public transport, a series of problems will appear.First of all,it will bring about more air pollution,a large amount of polluted air given off by cars do great harm to our health.What’s more, as the existing roads are not so wide for the increasing number of cars,undoubtedly,traffic jams will become more and more serious. Last but not least, cars also place burden on the public facilities in providing more parking lots. As far as I am concerned,everything has its advantages and disadvantages. It’s high time that effective action must be token to limit the ever growing number of cars, the government should take measures to control the air pollution from the cars. Some roads should be widened and more new roads should be constructed. Only in this way，will people benefit from the popularity of cars. 坏的 Nowadays, with the rapid improvement of people's living standards, cars have become an indispensable part of people's lives,so that more and more people have a car of their own, especially in cities.It brings some benefit for us but also causes many problems at the same time. For one thing,it's no doubt that that cars provide much convenience for people to go where they want to quickly and easily. Especially on weekday,driving a car can save a lot of time for us to go to work.When some places are too far away from our home, driving our own car is also convenient, we can go wherever we want. However,for another, too many cars will lead to the pressure of public transport, a series of problems will appear.First of all,it will bring about more air pollution,a large amount of polluted air given off by cars do great harm to our health .What's more, as the existing roads are not so wide for the increasing number of cars,undoubtedly,traffic jams will become more and more serious. Last but not least, cars also place burden on the public facilities in providing more parking lots. As far as I am concerned,everything has its advantages and disadvantages. It's high time that effective action must be token to limit the ever growing number of cars, the government should take measures to control the air pollution from the cars. Some roads should be widened and more new roads should be constructed. Only in this way,will people benefit from the popularity of cars. 篇二：雅思作文高分范文：私家车的利与弊 智课网IELTS备考资料 雅思作文高分范文：私家车的利与弊 The way的用法及其含义（二） 二、the way在句中的语法作用 the way在句中可以作主语、宾语或表语： 1.作主语 The way you are doing it is completely crazy.你这个干法简直发疯。 The way she puts on that accent really irritates me. 她故意操那种口音的样子实在令我恼火。The way she behaved towards him was utterly ruthless. 她对待他真是无情至极。 Words are important, but the way a person stands, folds his or her arms or moves his or her hands can also give us information about his or her feelings. 言语固然重要,但人的站姿,抱臂的方式和手势也回告诉我们他(她)的情感。 2.作宾语 I hate the way she stared at me.我讨厌她盯我看的样子。 We like the way that her hair hangs down.我们喜欢她的头发笔直地垂下来。 You could tell she was foreign by the way she was dressed. 从她的穿著就可以看出她是外国人。 She could not hide her amusement at the way he was dancing. 她见他跳舞的姿势，忍俊不禁。 3.作表语 This is the way the accident happened.这就是事故如何发生的。 Believe it or not, that's the way it is. 信不信由你, 反正事情就是这样。 That's the way I look at it, too. 我也是这么想。 That was the way minority nationalities were treated in old China. 那就是少数民族在旧中 我国艺术歌曲钢琴伴奏-精 2020-12-12 【关键字】传统、作风、整体、现代、快速、统一、发展、建立、了解、研究、特点、突出、关键、内涵、情绪、力量、地位、需要、氛围、重点、需求、特色、作用、结构、关系、增强、塑造、借鉴、把握、形成、丰富、满足、帮助、发挥、提高、内心 【摘要】艺术歌曲中，伴奏、旋律、诗歌三者是不可分割的重 要因素，它们三个共同构成一个统一体，伴奏声部与声乐演唱处于 同样的重要地位。形成了人声与器乐的巧妙的结合，即钢琴和歌唱 的二重奏。钢琴部分的音乐使歌曲紧密的联系起来，组成形象变化 丰富而且不中断的套曲，把音乐表达的淋漓尽致。 【关键词】艺术歌曲；钢琴伴奏；中国艺术歌曲 艺术歌曲中，钢琴伴奏不是简单、辅助的衬托，而是根据音乐 作品的内容为表现音乐形象的需要来进行创作的重要部分。准确了 解钢琴伴奏与艺术歌曲之间的关系,深层次地了解其钢琴伴奏的风 格特点,能帮助我们更为准确地把握钢琴伴奏在艺术歌曲中的作用 和地位，从而在演奏实践中为歌曲的演唱起到更好的烘托作用。 一、中国艺术歌曲与钢琴伴奏 “中西结合”是中国艺术歌曲中钢琴伴奏的主要特征之一，作 曲家们将西洋作曲技法同中国的传统文化相结合，从开始的借鉴古 典乐派和浪漫主义时期的创作风格，到尝试接近民族乐派及印象主 义乐派的风格，在融入中国风格的钢琴伴奏写作，都是对中国艺术 歌曲中钢琴写作技法的进一步尝试和提高。也为后来的艺术歌曲写 作提供了更多宝贵的经验，在长期发展中，我国艺术歌曲的钢琴伴 奏也逐渐呈现出多姿多彩的音乐风格和特色。中国艺术歌曲的钢琴 写作中，不可忽略的是钢琴伴奏织体的作用，因此作曲家们通常都以丰富的伴奏织体来烘托歌曲的意境，铺垫音乐背景，增强音乐感染力。和声织体，复调织体都在许多作品中使用，较为常见的是综合织体。这些不同的伴奏织体的歌曲，极大限度的发挥了钢琴的艺术表现力，起到了渲染歌曲氛围，揭示内心情感，塑造歌曲背景的重要作用。钢琴伴奏成为整体乐思不可缺少的部分。优秀的钢琴伴奏织体，对发掘歌曲内涵，表现音乐形象，构架诗词与音乐之间的桥梁等方面具有很大的意义。在不断发展和探索中，也将许多伴奏织体使用得非常娴熟精确。 二、青主艺术歌曲《我住长江头》中钢琴伴奏的特点 《我住长江头》原词模仿民歌风格，抒写一个女子怀念其爱人的深情。青主以清新悠远的音乐体现了原词的意境，而又别有寄寓。歌调悠长，但有别于民间的山歌小曲；句尾经常出现下行或向上的拖腔，听起来更接近于吟哦古诗的意味，却又比吟诗更具激情。钢琴伴奏以江水般流动的音型贯穿全曲，衬托着气息宽广的歌唱，象征着绵绵不断的情思。由于运用了自然调式的旋律与和声，显得自由舒畅，富于浪漫气息，并具有民族风味。最有新意的是，歌曲突破了“卜算子”词牌双调上、下两阕一般应取平行反复结构的惯例，而把下阕单独反复了三次，并且一次比一次激动，最后在全曲的高音区以ff结束。这样的处理突出了思念之情的真切和执著，并具有单纯的情歌所没有的昂奋力量。这是因为作者当年是大革命的参加者，正被反动派通缉，才不得不以破格的音乐处理，假借古代的 介绍北京的英语作文1篇 篇一MyFamily Ilovemyfamily,becauseIhaveahappyfamily. MyfatherisanEnglishteacher.HisnameisJacky.Heisthirty-eight.Helikesplay ingbasketball.What’smymotherjop?Issheateacher?Yes,you’reright!Mymotherisverykindandnice,sheisthirty-seven.Mymotherisalways laboriouswork.Ilovemyparents! OnStaurdayandSunday,Ioftengotothelibraryandplaythepiano,Myfathergot oplaybasketball.Sometimes,wewatchTVandlistentomusicathome. Ilovemyfamily.BecauseI’mveryhappytolivewithmyparentstogether! 篇二MyFamily MyFamily Everyonehasafamily.Weliveinitandfeelverywarm.Therearethreepersonsin myfamily,mymother,fatherandI.Welivetogetherveryhappilyandtherearema nyinterestingstoriesaboutmyfamily. Myfatherisahard-workingman.Heworksasadoctor.Healwaystrieshisbesttoh elpevery,patientandmakepatientscomfortable.Butsonetimesheworkssohard thathecan”trememberthedate. 定冠词the的用法： 定冠词the与指示代词this ,that同源,有“那(这)个”的意思,但较弱,可以和一个名词连用,来表示某个或某些特定的人或东西. (1)特指双方都明白的人或物 Take the medicine.把药吃了. (2)上文提到过的人或事 He bought a house.他买了幢房子. I've been to the house.我去过那幢房子. (3)指世界上独一无二的事物 the sun ,the sky ,the moon, the earth (4)单数名词连用表示一类事物 the dollar 美元 the fox 狐狸 或与形容词或分词连用,表示一类人 the rich 富人 the living 生者 (5)用在序数词和形容词最高级,及形容词等前面 Where do you live?你住在哪? I live on the second floor.我住在二楼. That's the very thing I've been looking for.那正是我要找的东西. (6)与复数名词连用,指整个群体 They are the teachers of this school.(指全体教师) They are teachers of this school.(指部分教师) (7)表示所有,相当于物主代词,用在表示身体部位的名词前 She caught me by the arm.她抓住了我的手臂. (8)用在某些有普通名词构成的国家名称,机关团体,阶级等专有名词前 the People's Republic of China 中华人民共和国 the United States 美国 (9)用在表示乐器的名词前 She plays the piano.她会弹钢琴. (10)用在姓氏的复数名词之前,表示一家人 the Greens 格林一家人(或格林夫妇) (11)用在惯用语中 in the day, in the morning... the day before yesterday, the next morning... in the sky... in the dark... in the end... on the whole, by the way... 汽车的重要性《英语作文》 The automobile has become one of the most important means/ways of transportation in the world since it was invented. The automobile has completely changed the lifestyles of almost all the people in the world. In the past, animals like horses and camels were used for traveling and transporting goods. Automobiles are more comfortable and faster. Automobiles have also made it possible for us to transport large quantities of goods and people at the same time. Besides, the invention of the automobile has provided jobs for millions of people all over the world. 翻译： 汽车已经成为世界上最重要的交通工具之一，因为它是发明的。汽车已经完全改变了世界上几乎所有的人的生活方式。 在过去，像马和骆驼的动物被用来运送货物。汽车更舒适，更快速。汽车也使我们能够在同一时间运送大量货物和人。 此外，汽车的发明为全世界上百万的人提供了工作。 三一文库（https://www.sodocs.net/doc/054439535.html,） 〔我想去北京英语作文〕 我想去北京的英语作文如何写？那么，下面是小编给大家整理收集的我想去北京英语作文，供大家阅读参考。 我想去北京英语作文1 I’d like to go to a beautiful place. I think it would be Beijing. Beijing is not only our capital city, but also a famous city with long history and wonderful culture. Beijing is also China’s political and cultural center. There’re many old places of great interest, such as the Great Wall, the Summer Palace, the Forbidden City, the Temple of Heaven, and Tiananmen Square. Once you see Tiananmen Square, you will think of Beijing. It has been the symbol of Beijing since 1949. 我想去北京英语作文2 I went to Beijing more than eight times. Beijing is the capital of China. It’s a big city. I am very familiar with Beijing. It takes an hour and forty minutes from Nantong to Beijing by plane. There are many tall buildings in Beijing. It’s a modern city. My family visited the Great Wall, the Summer “tｈｅwａｙ+从句”结构的意义及用法 首先让我们来看下面这个句子: Ｒead the foｌloｗｉnｇpassagｅａnd talkａbout ｉt wi ｔh your classmaｔes．Try tｏｔeｌl whaｔyｏu thiｎk ｏf Tom aｎd ｏｆｔhe ｗay the chiｌｄrenｔrｅated ｈim. 在这个句子中，ｔhe waｙ是先行词,后面是省略了关系副词that或in whｉch的定语从句。 下面我们将叙述“the ｗaｙ+从句”结构的用法。 1.tｈe wａy之后，引导定语从句的关系词是tｈat而不是hoｗ,因此，<<现代英语惯用法词典＞＞中所给出的下面两个句子是错误的：Ｔhｉs is ｔｈeｗayｈowｉtｈａppened. This is the way how he ａlwａｙs treats me. 2．在正式语体中,thaｔ可被in which所代替;在非正式语体中，ｔhat则往往省略。由此我们得到theｗay后接定语从句时的三种模式：1) tｈe ｗaｙ＋ｔhａt-从句２）the way +ｉn whiｃh－从句3) the ｗay +从句 例如：Ｔｈe way(in whiｃh ，thａt) ｔhｅｓｅｃomｒade ｓloｏｋａｔｐrobｌems is wrong．这些同志看问题的方法 不对。 Ｔｈｅｗａy(that ,ｉn ｗhiｃh)yoｕ’ｒe doinｇit is comple ｔeｌy crａzy.你这么个干法,简直发疯。 Wｅａdmiｒｅd him for thｅｗay ｉｎｗhｉch he fａｃeｓdiｆficultieｓ． Waｌlａｃe ａｎd Ｄarwiｎｇreed ｏn the way ｉｎwhi ｃh ｄｉfｆｅrｅnt forms ｏf life had ｂegｕn.华莱士和达尔文对不同类型的生物是如何起源的持相同的观点。 Thｉs is ｔｈe ｗaｙ（tｈａｔ) hｅdｉd it. I lｉkeｄｔhe waｙ(ｔhat) ｓｈeｏｒganized ｔhe ｍeetｉng． 3.theｗay(tｈat)有时可以与hｏw(作“如何”解）通用。例如： That’s tｈe ｗaｙ(tｈaｔ) shｅspoke. = Tｈat’s how shｅspoke. 汽车英文演讲稿 篇一：汽车英语演讲稿 Good morning everyone ,today, the topic of my lecture（演讲） is “Do you love automobiles（'tmbilz）”. before I start my speech ,I want to ask a question,did there anybody present had seen the movie”the Fast and the Furious['fjrs]”.There are many cars of different styles in the movie,for example ,when you see the movie,you can find roadsters（跑车） just like Porsche（保时捷） GT3,sports utility (通用的）vehicles （车）SUV such as Volkswagen ['f:lks,va:gn]Touareg ['twɑ:reɡ](大众途锐）,even armored cars ,all of them are so powerful and beautiful. When I was a child,I dreamed I can have a car like FORD GT 40,this racing bike（跑车） is amazing and fantastic,but as time goes on ,my hobby is changing,now my favorite car is Jeep Rubicon,this is a car I really want ,it’s dynamic performance（性能） and off-road （越野） performance is top-ranking（一流的） ,which other ordinary SUV is unable to compare; the shape and color of this car is magnificent (华丽的） [mg'nfs()nt],and it’s gear-shift system（齿轮转 小学一年级介绍北京的英语作文 Beijing is an ancient city with a long history. Back in 3000 years ago in Zhou dynasty, Beijing, which was called Ji at the moment, had been named capital of Yan. Thereafter, Liao, Jin, Yuan, Ming and Qing dynasty all made Beijing their capital. Therefore, Beijing was famous for "Capital of a thousand years". The long history leaves Beijing precious cultural treasure. Winding for several kilometers in Beijing area, the Great Wall is the only man-made structure that could been seen in the space. The Summer Palace is a classic composition of ancient royal gardens, and the Forbidden City is the largest royal palaces in the world. Tiantan is where the emperor used to fete their ancestors, and also the soul of Chinese ancient constructions. The four sites above has been confirmed world cultural heritage by UNESCO. However, the best representatives for Beijing are the vanishing Hutongs and square courtyards. Through hundreds of years, they have become symbol of Beijing's life. Tian'anmen square being still brilliant today with cloverleaf junctions and skyscrapers everywhere, the old-timey scene and modern culture are combined to present a brand new visage of Beijing. As Beijing has been confirmed home city of Olympics 2008, the spirit of "green Olympics, scientific Olympics and humanized Olympic" will surely bring more and more changes to Beijing, promote the development of sports and Olympics in China as well as in the world, and strengthen the friendly communications between Chinese and foreign people. 北京是一个有着悠久历史的古城。 早在 3000 年前的周朝,北京,这叫霁,被命 名为首都燕。此后,辽、金、元、明、清都是北京首都。因此,北京著名的一千年 的“资本”。 悠久的历史使北京宝贵的文化瑰宝。绕组在北京地区几公里,长城是唯一的 人造结构,可以在空间。 颐和园是古代皇家园林的经典组合,和故宫是世界上最大 的皇家宫殿。 天坛是皇帝用来祭祀他们的祖先的地方,也是中国古代建筑的灵魂。 上面的四个网站已经确认被联合国教科文组织世界文化遗产。然而,北京最好的 代表是消失的胡同和广场庭院。数百年来,他们已经成为北京的生活的象征。天 安门广场到处都在今天依然灿烂的蝶式路口和摩天大楼的,古色古香的场景和现 代文化相结合,提出一个全新的北京的面貌。 随着北京 2008 年奥运会已被证实的家乡,精神的“绿色奥运、科技奥英语作文关于共享单车的篇精编
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