• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    The Three-Pion Decays of the a1(1260)?

    2018-07-09 06:46:36XuZhang張旭andJuJunXie謝聚軍
    Communications in Theoretical Physics 2018年7期
    關(guān)鍵詞:張旭

    Xu Zhang(張旭)and Ju-Jun Xie(謝聚軍)

    Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China

    University of Chinese Academy of Sciences,Beijing 101408,China

    1 Introduction

    In the naive quark model,mesons are composed of a quark-antiquark pair.This picture works extremely well for most of the known mesons.[1]However,there are a growing set of experimental observations of resonancelike structures,which cannot be explained by the quarkantiquark model.[1?3]Even among the seemingly well established and understood mesons,some of them may be more complicated than originally thought.[4?5]One such example is the lowest-lying axial-vector mesons.The a1(1260)is a ground state of axial-vector resonance with quantum numbers IG(JPC)=1?(1++).However,it was found that the a1(1260)could be dynamically generated from the interactions of K?ˉK and ρπ channels and the couplings of the a1(1260)to these channels can be also obtained at the same time.[6]Based on these results,the radiative decay of a1(1260)meson was studied in Refs.[7–8],where the theoretical calculations agree with the experimental values within uncertainties.In Ref.[9]the lattice result for the coupling constant of a1(1260)to the ρπ channel is also close to the value obtained in Ref.[6].Besides,the effects of the next-to-leading order chiral potential on the dynamically generated axial-vector mesons were studied in Ref.[10].It was found that the inclusion of the higher-order kernel does not change the results obtained with the leading-order kernel in any significant way,which gives more supports to the dynamical picture of the a1(1260)state.[6,10?11]

    On the other hand,it is suggested that the a1(1260)resonance is a candidate of the chiral partner of the ρ meson[12?14]described as a qˉq state.The nature of a1(1260)has been studied by calculating physical observables such as the τ decay spectrum into three pions[15?18]or the multipions decays of light vector mesons.[19?20]Recently,the production of a1(1260)resonance in the reaction of π?p →(1260)p within an effective Lagrangian approach was studied in Ref.[21]based on the results obtained in chiral unitary approach.Furthermore,a general method was developed in Ref.[22]to analyze the mixing structure of hadrons consisting of two components of quark and hadronic composites,and the nature of the a1(1260)was explored with the method,[22]where it was found that the a1(1260)resonance has comparable amounts of the elementary component qˉq to the ρπ.In Ref.[23],the Ncbehavior of a1(1260)was studied using the unitarized chiral approach,and it was found that the main component of a1(1260)is not qˉq.A probabilistic interpretation of the compositeness at the pole of a resonance was been derived in Ref.[24],where it was obtained that,for a1(1260),the compositeness and elementariness are similar.Furthermore,the a1(1260)can also appear as a gauge boson of the hidden local symmetry,[25?26]which is recently reconciled with the five-dimensional gauge field of the holographic QCD.[27?28]Yet,the nature of the a1(1260)state is still not well understood.The only way to understand its nature is to examine it from all possible perspectives,both experimentally and theoretically.

    On the experimental side,for the a1(1260)resonance,the experimental width Γa1(1260)=(250–600)MeV as-signed by the Particle Data Group(PDG)[1]has large uncertainty.While most experiments and phenomenological extractions agree on the mass of the a1(1260)leading to a PDG value of Ma1(1260)=(1230±40)MeV,which is more precisely than its width.A new COMPASS measurement in Ref.[29]provides a much smaller uncertainty of the width Γa1(1260)=367±MeV and mass Ma1(1260)=1255±6+7?17MeV.Therefore,study of the total decay width and the decay behaviors of a1(1260)is important both on experimental and theoretical sides,and can also provide beneficial information about the internal structure of it.

    The best knowledge about a1(1260)resonance decay channels and branching ratio comes from hadronic τ decay measurements,[30?32]while the ρπ decay mode in the three-pion decays,which the dominant decay channel of a1(1260),is the most important one.[1,33?34]In this work,we study the three-pion decays of the a1(1260)by considering only the dominant a1(1260)→ ρπ intermediate process and,in this calculation,we take the coupling constant of a1(1260)to ρπ channel in S-wave as that was obtained in Ref.[6].In this respect,our calculations are based on the dynamical picture of the a1(1260),which is a dynamically generated state from the interactions ofK?and ρπ coupled channels.We calculate the energy dependence of the partial decay width of Γa1(1260)→3πas a function of the mass of a1(1260),which could be tested by future experiments when the precise measurements for the mass and width of the a1(1260)resonance were done.

    This article is organized as follows.In Sec.2,formalism and ingredients used in the calculation are given.In Sec.3,the results are presented and discussed.Finally,a short summary is given in the last section.

    2 Formalism and Ingredients

    We study the decay of a1(1260)→ 3π with the assumption that the a1(1260)is dynamically generated from the interactions of ρπ andK?in coupled channel,thus this decay can proceed via a1(1260)→ ρπ → 3π as shown in Fig.1,where we take the(1260)→ π+π+π?and π+π0π0into account.It is easy to know that the two diagrams in Fig.1 give the same contributions to the a1(1260)→ 3π decay.Hence,we consider only the Fig.1(a)in the following calculation and we multiply by a factor two to the final result.

    Fig.1 The dominant diagrams for the decay of a1(1260)→ 3π.(a)(1260)→ π+π+π? and(b)(1260)→ π+π0π0.

    2.1 Decay Amplitude at Tree Level

    In order to evaluate the partial decay width of a1(1260)→ 3π,we need the decay amplitudes of the tree level diagrams shown in Fig.1,where the process is described as the a1(1260)decaying to ρπ and then the ρ decaying into ππ.As mentioned above,a1(1260)results as dynamically generated from the interactions of the ρπ andK?in coupled channels.We can write theρ0π+vertex as

    whereis the polarization vector of a1(1260)and εμthe polarization vector of the ρ.The ga1ρπis the coupling of the a1(1260)to the ρπ channel and can be obtained from the residue in the pole of the scattering amplitude in I=1.We take ga1ρπ=(?3795+i2330)MeV and ga1KˉK?=(1872?i1468)MeV as obtained in Ref.[6].We can see that the a1(1260)has large coupling to ρπ channel comparing to theK?channel.

    To compute the decay amplitude,we also need the structure of the ρππ vertices,which can be evaluated by means of hidden gauge symmetry Lagrangian describing the vector-pseudoscalar-pseudoscalar(VPP)interaction,[25,35?37]given by

    where the symbolstands for the trace in SU(3)and g=mV/2f,with mV=mρa(bǔ)nd f=93 MeV the pion decay constant.The matrices P and V contain the nonet of the pseudoscalar mesons and the one of the vectors respectively.

    From the Lagrangian of Eq.(2),the vertex of ρ0π+π?can be written as??Note that from the local hidden gauge approach is 5.89,while the equivalent quantity gρππ used in Ref.[38]is 6.05.They differ in 2.5%.

    where p1and p2are the momenta of π?and π+mesons,respectively.

    We can now straightforwardly construct the decay amplitude for(1260)→ π+π+π?decay corresponding to the tree diagram shown in Fig.1(a):

    where the two terms stand for the contributions with the ρ0in theand in thesubsystem,and q1=p1+p2and q2=p1+p3.

    We take the energy dependent decay width of Γρ.Because the dominant decay channel of ρ is ππ,we take

    with Γon=149.1 MeV,and

    withthe invariant mass square of the π+π?system corresponding the two terms shown in Eq.(4).We take mρ=775.26 MeV in this work.

    It is worthy to mention that the parametrization of the width of the ρ meson shown in Eq.(5)is common and it is meant to take into account the phase space of each decay mode as a function of the energy.[39?41]In the present work we take explicitly the phase space for the P-wave decay of the ρ into two pions.

    Besides,in Eq.(4),Fρππis the form factor of ρ0.In our present calculation we adopt the following form as used in previous works[41?45]

    where Λρis the cutoff parameter of ρ0.

    2.2 Decay Amplitude for the Triangular Loop

    In addition to the tree level diagrams shown in Fig.1,we study also the contributions of ππ→ππ and K→ππ final state interaction(FSI).For this purpose,we use the triangular mechanism contained in the diagrams shown in Fig.2,consisting in the rescatering of the ππ and Kpairs.The rescattering of ππ and Kin coupled channels dynamically generates the f0(500)and f0(980)resonances.

    Fig.2 Triangular loop contributions to the(1260)→ π+π?π+decay.

    We can write explicitly the decay amplitudes for the triangular diagrams shown in Fig.2 as(see also Ref.[46],where more details can be found)

    whereandare the meson-meson scattering amplitudes obtained in the chiral unitary approach in Ref.[47],which depend on the invariant mass of π+π?.The tππ→ππandin the first and second terms in Eqs.(9)and(10)depend onand,respectively.In addition,in Eq.(9)the quantities I1and I2are given by

    3 Numerical Results and Discussion

    With the decay amplitudes obtained above,we can easily get the total decay width of a1(1260)→ 3π which

    with q the four-momentum of the a1(1260).Here we give explicitly the results for the tree diagrams,as an example,

    With all the ingredients obtained above,one can easily get the total decay width of a1(1260)→ 3π by performing the integration of M12and cosθ?.The results for Γ as a function of Λρis shown in Fig.3 with Ma1=1230 MeV.From Fig.3 one can see that the results for Γ are not sensitive to the value of Λρ,therefore,we fix Λρ=1500 MeV in the next calculations.

    Fig.3 The total decay width of a1(1260)→ 3π as a function of the cutoff parameter Λρ.

    Fig.4 The π+π? invariant mass distribution for a1(1260)→ 3π as a function of the invariant mass of the π+π? system.The experimental data are taken from Ref.[50].

    However,since a1(1260)has large total decay width which should be taken into account.For this purpose we replace the dΓ in Eq.(15)by d:

    In Fig.4,we show the numerical results for π+π?invariant mass distributions.We compare also our theoretical calculations with the experimental results of Ref.[50]measured in the decay of τ→ π?π?π+ντ.In Fig.4 we see that the tree level alone can describe well the experimental data around the ρ peak.This is attributed to the effect of the ρ0off shell propagator.The implementation of the

    where the spectral function S(m2)is defined as contributions of the triangle loop diagrams is responsible for the enhancement of the invariant mass distribution at the lower invariant masses,where the f0(500)resonance appears.There is also a small peak around the Kmass threshold,where the f0(980)resonance appears.

    Fig.5 The total decay width of a1(1260)→ 3π as a function of Ma1.

    The numerical results in Fig.4 show how the most drastic change in the line shape of the the invariant π+π?mass distribution is caused by the tree diagram alone in Fig.1 and,as mentioned before,this is tied to the ρ0contribution,which appears at tree level because of the large coupling of a1(1260)to ρπ channel obtained in the chiral unitary approach.[6]

    Next, we calculate the total decay width of(1260) → π+π+π?as a function of the mass of a1(1260).The numerical result is shown in Fig.5.The width rises rapidly with increasing Ma1in the mass range Ma1<1300 MeV,while it goes to flat when Ma1>1400 MeV.Besides,we get Γ=166 MeV at Ma1=1230 MeV.There is still no precise measurement about the(1260)→π+π+π?decay,we cannot compare our result with experiment.Note that the width Γa1≡ Γa01→π+π?π0was studied in Ref.[19],and Γa1=860 MeV was obtained at Ma1=1230 MeV.One can see that the theoretical result in Ref.[19]is much different with us.On the other hand,there are two peaks in the solid curve in Fig.5,which are attributed to the effect of the ππ → ππ and K→ππ final state interactions.We hope that the future experiments could test the model calculations.

    So far we have assumed that the a1(1260)resonance is fully made from ρπ andK?interaction.The pole position(?/2)is identified from the zero of the denominator of the scattering amplitudes in the complex plane,and the effective couplings ga1ρπand ga1KˉK?are calculated from the residues of the scattering amplitudes at the complex pole.We know that the a1(1260)Breit-Wigner parameters,Ma1and Γa1,deviate from its pole parameters by a large amount and are reaction dependent.[1]On the other hand,we have no information on how the effective couplings obtained at the pole position change with varying Ma1,and therefore,we cannot include the uncertainties of these effective couplings without making further assumptions.Besides,there are hints that the a1(1260)resonance could have also other components as mention above,thus,there should be also contribution from a1(1260)→ f0(500)π → 3π[1]in the tree level.However,the information about this contribution is very scarce.We will leave such studies to a future work.

    4 Summary

    In this work,we evaluate the partial decay width of the(1260)→ π+π+π?with the assumption that the a1(1260)is dynamically generated from the coupled channel ρπ andK?interactions.The dominant tree level diagrams that proceed via(1260)→ ρ0π+→ π+π+π?are considered.Besides,we also take into account the final state interactions of ππ → ππ and K→ ππ.It is found that the contributions from ππ → ππ and K→ππ are small compared to the tree level diagram,but they change the π+π?invariant mass distributions of the a1(1260)→ 3π decay.

    The results that we obtained for the π+π?invariant mass distributions are in a fair agreement with the experimental measurements for the τ→ π?π?π+ντdecay.This provides new support for the molecular picture of a1(1260).Furthermore,we calculate also the total decay width as a function of the mass of a1(1260),it is found that our result is different with other model calculations.Thus,we hope that the further experimental observations of the π+π?and π+π+π?mass distributions would then test these model calculations and provide vary valuable information on the relevance of the ρπ component in the a1(1260)wave function.

    [1]C.Patrignani,et al.,[Particle Data Group],Chin.Phys.C 40(2016)100001.

    [2]E.Klempt and A.Zaitsev,Phys.Rep.454(2007)1.

    [3]N.Brambilla,et al.,Eur.Phys.J.C 74(2014)2981.

    [4]V.Baru,J.Haidenbauer,C.Hanhart,et al.,Phys.Lett.B 586(2004)53.

    [5]T.Hyodo,D.Jido,and A.Hosaka,Phys.Rev.C 78(2008)025203.

    [6]L.Roca,E.Oset,and J.Singh,Phys.Rev.D 72(2005)014002.

    [7]L.Roca,A.Hosaka,and E.Oset,Phys.Lett.B 658(2007)17.

    [8]H.Nagahiro,L.Roca,A.Hosaka,and E.Oset,Phys.Rev.D 79(2009)014015.

    [9]C.B.Lang,L.Leskovec,D.Mohler,and S.Prelovsek,J.High Energy Phys.1404(2014)162.

    [10]Y.Zhou,X.L.Ren,H.X.Chen,and L.S.Geng,Phys.Rev.D 90(2014)014020.

    [11]M.F.M.Lutz,and E.E.Kolomeitsev,Nucl.Phys.A 730(2004)392.

    [12]S.Weinberg,Phys.Rev.Lett.18(1967)507.

    [13]C.W.Bernard,A.Duncan,J.LoSecco,and S.Weinberg,Phys.Rev.D 12(1975)792.

    [14]G.Ecker,J.Gasser,A.Pich,and E.de Rafael,Nucl.Phys.B 321(1989)311.

    [15]D.Gomez Dumm,A.Pich,and J.Portoles,Phys.Rev.D 69(2004)073002.

    [16]M.Wagner and S.Leupold,Phys.Rev.D 78(2008)053001.

    [17]D.G.Dumm,P.Roig,A.Pich,and J.Portoles,Phys.Lett.B 685(2010)158158.

    [18]I.M.Nugent,T.Przedzinski,P.Roig,et al.,Phys.Rev.D 88(2013)093012.

    [19]N.N.Achasov and A.A.Kozhevnikov,Phys.Rev.D 71(2005)034015.

    [20]P.Lichard and J.Juran,Phys.Rev.D 76(2007)094030.

    [21]C.Cheng,J.J.Xie,and X.Cao,Commun.Theor.Phys.66(2016)675.

    [22]H.Nagahiro,K.Nawa,S.Ozaki,et al.,Phys.Rev.D 83(2011)111504.

    [23]L.S.Geng,E.Oset,J.R.Pelaez,and L.Roca,Eur.Phys.J.A 39(2009)81.

    [24]Z.H.Guo and J.A.Oller,Phys.Rev.D 93(2016)096001.

    [25]M.Bando,T.Kugo,and K.Yamawaki,Phys.Rep.164(1988)217.

    [26]N.Kaiser and U.G.Mei?ner,Nucl.Phys.A 519(1990)671.

    [27]T.Sakai and S.Sugimoto,Prog.Theor.Phys.113(2005)843.

    [28]T.Sakai and S.Sugimoto,Prog.Theor.Phys.114(2005)1083.

    [29]M.Alekseev,et al.,[COMPASS Collaboration],Phys.Rev.Lett.104(2010)241803.

    [30]D.M.Asner,et al.,[CLEO Collaboration],Phys.Rev.D 61(2000)012002.

    [31]R.A.Briere,et al.,[CLEO Collaboration],Phys.Rev.Lett.90(2003)181802.

    [32]T.E.Coan,et al.,[CLEO Collaboration],Phys.Rev.Lett.92(2004)232001.

    [33]R.R.Akhmetshin,et al.,[CMD-2 Collaboration],Phys.Lett.B 466(1999)392.

    [34]P.Salvini,et al.,[OBELIX Collaboration],Eur.Phys.J.C 35(2004)21.

    [35]M.Bando,T.Kugo,S.Uehara,et al.,Phys.Rev.Lett.54(1985)1215.

    [36]U.G.Mei?ner,Phys.Rep.161(1988)213.

    [37]M.Harada and K.Yamawaki,Phys.Rep.381(2003)1.

    [38]J.J.Xie,C.Wilkin,and B.S.Zou,Phys.Rev.C 77(2008)058202.

    [39]H.C.Chiang,E.Oset,and L.C.Liu,Phys.Rev.C 44(1991)738.

    [40]C.Hanhart,Y.S.Kalashnikova,and A.V.Nefediev,Phys.Rev.D 81(2010)094028.

    [41]J.J.Xie,B.S.Zou,and H.C.Chiang,Phys.Rev.C 77(2008)015206.

    [42]K.Tsushima,A.Sibirtsev,and A.W.Thomas,Phys.Rev.C 62(2000)064904.

    [43]A.M.Gasparyan,J.Haidenbauer,C.Hanhart,and J.Speth,Phys.Rev.C 68(2003)045207.

    [44]J.J.Xie and B.S.Zou,Phys.Lett.B 649(2007)405.

    [45]J.J.Xie,Phys.Rev.C 92(2015)065203.

    [46]F.Aceti,L.R.Dai,and E.Oset,Phys.Rev.D 94(2016)096015.

    [47]J.A.Oller and E.Oset,Nucl.Phys.A 620(1997)438,Erratum:[Nucl.Phys.A 652(1999)407].

    [48]F.Aceti,J.M.Dias,and E.Oset,Eur.Phys.J.A 51(2015)48.

    [49]F.Aceti,J.J.Xie,and E.Oset,Phys.Lett.B 750(2015)609.

    [50]H.Albrecht,et al.,[ARGUS Collaboration],Z.Phys.C 58(1993)61.

    猜你喜歡
    張旭
    THE TIME DECAY RATES OF THE CLASSICAL SOLUTION TO THE POISSON-NERNST-PLANCK-FOURIER EQUATIONS IN R3*
    張旭作品賞析
    《古詩(shī)四帖》與晚明鑒藏家的“張旭”概念
    書(shū)法家肚子痛
    Effects of Froude number and geometry on water entry of a 2-D ellipse *
    張旭典藏欣賞
    寶藏(2017年10期)2018-01-03 01:53:02
    『脫發(fā)』的大樹(shù)
    淺談氧化還原反應(yīng)的實(shí)際應(yīng)用
    許淇·中國(guó)畫(huà)《張旭》
    散文詩(shī)(2017年2期)2017-06-05 15:11:09
    打針
    久久久国产欧美日韩av| 男人舔女人下体高潮全视频| 国产xxxxx性猛交| 亚洲熟妇中文字幕五十中出 | 免费久久久久久久精品成人欧美视频| 久久久久久久久中文| 国产亚洲精品久久久久久毛片| 巨乳人妻的诱惑在线观看| 久久精品人人爽人人爽视色| 这个男人来自地球电影免费观看| 夫妻午夜视频| 麻豆成人av在线观看| 美女大奶头视频| 黑丝袜美女国产一区| 在线观看日韩欧美| 亚洲 欧美一区二区三区| 亚洲欧美激情在线| 国产欧美日韩一区二区三| 男女下面插进去视频免费观看| 国产精品秋霞免费鲁丝片| 精品国产乱子伦一区二区三区| 久热爱精品视频在线9| 精品国产一区二区三区四区第35| 男女下面插进去视频免费观看| 少妇的丰满在线观看| 99久久99久久久精品蜜桃| 亚洲 欧美 日韩 在线 免费| 国产欧美日韩一区二区三| 一个人观看的视频www高清免费观看 | 亚洲专区字幕在线| 亚洲自拍偷在线| 国产一区二区激情短视频| 一区二区三区精品91| 色尼玛亚洲综合影院| 国产成+人综合+亚洲专区| 99国产极品粉嫩在线观看| 久久精品人人爽人人爽视色| www国产在线视频色| 亚洲av片天天在线观看| 波多野结衣av一区二区av| 90打野战视频偷拍视频| 亚洲一区高清亚洲精品| 午夜福利影视在线免费观看| 午夜福利欧美成人| 1024视频免费在线观看| 欧美中文综合在线视频| 老司机在亚洲福利影院| 18禁国产床啪视频网站| 亚洲色图 男人天堂 中文字幕| 中文字幕最新亚洲高清| 亚洲成人久久性| 十八禁网站免费在线| 91国产中文字幕| 91大片在线观看| 亚洲熟女毛片儿| 亚洲视频免费观看视频| 大香蕉久久成人网| 日日摸夜夜添夜夜添小说| 悠悠久久av| 国产欧美日韩精品亚洲av| 两性夫妻黄色片| 午夜免费鲁丝| 亚洲av成人不卡在线观看播放网| 丝袜美腿诱惑在线| 大码成人一级视频| 在线观看66精品国产| 国产av一区二区精品久久| 免费人成视频x8x8入口观看| 国产精品一区二区在线不卡| 女人被躁到高潮嗷嗷叫费观| 午夜福利在线免费观看网站| 大码成人一级视频| 久久国产精品影院| 亚洲精品美女久久av网站| 母亲3免费完整高清在线观看| 中出人妻视频一区二区| 欧美精品亚洲一区二区| 在线永久观看黄色视频| 十八禁人妻一区二区| xxx96com| 日本免费一区二区三区高清不卡 | 两性夫妻黄色片| 50天的宝宝边吃奶边哭怎么回事| 欧美+亚洲+日韩+国产| 国产三级黄色录像| 久久久久久亚洲精品国产蜜桃av| 亚洲国产精品合色在线| 少妇被粗大的猛进出69影院| 99riav亚洲国产免费| 国产精品一区二区在线不卡| 久久香蕉精品热| 国产xxxxx性猛交| videosex国产| 欧美激情高清一区二区三区| 视频在线观看一区二区三区| 久9热在线精品视频| 国产单亲对白刺激| 美女福利国产在线| 国产精品98久久久久久宅男小说| 欧美亚洲日本最大视频资源| 国产xxxxx性猛交| 天堂动漫精品| 99在线人妻在线中文字幕| 久久中文字幕一级| 99riav亚洲国产免费| 亚洲免费av在线视频| 亚洲 欧美一区二区三区| 亚洲色图av天堂| 午夜福利一区二区在线看| 夜夜爽天天搞| 精品国产乱子伦一区二区三区| 欧美一区二区精品小视频在线| 亚洲中文av在线| 99久久精品国产亚洲精品| 中文字幕精品免费在线观看视频| 他把我摸到了高潮在线观看| 精品熟女少妇八av免费久了| 亚洲一区中文字幕在线| 91麻豆精品激情在线观看国产 | 亚洲专区中文字幕在线| 午夜亚洲福利在线播放| 国产片内射在线| 精品一区二区三区视频在线观看免费 | 视频在线观看一区二区三区| 91精品国产国语对白视频| 日韩欧美国产一区二区入口| 亚洲黑人精品在线| 国产99久久九九免费精品| 97碰自拍视频| 亚洲国产欧美一区二区综合| 人人澡人人妻人| 日韩免费av在线播放| 淫秽高清视频在线观看| 亚洲成国产人片在线观看| 一本大道久久a久久精品| 精品一品国产午夜福利视频| 99香蕉大伊视频| 真人做人爱边吃奶动态| 国产又爽黄色视频| 青草久久国产| 美国免费a级毛片| 国产不卡一卡二| 又大又爽又粗| 99久久99久久久精品蜜桃| 免费少妇av软件| 国产精品 国内视频| 淫妇啪啪啪对白视频| 亚洲全国av大片| 中文字幕人妻丝袜制服| 日韩欧美在线二视频| 超碰97精品在线观看| 美女高潮到喷水免费观看| 老司机午夜十八禁免费视频| 亚洲精品一卡2卡三卡4卡5卡| 88av欧美| 99久久综合精品五月天人人| 身体一侧抽搐| 亚洲国产精品一区二区三区在线| 亚洲精品av麻豆狂野| 无遮挡黄片免费观看| 国产精品久久久久久人妻精品电影| 正在播放国产对白刺激| 国产欧美日韩一区二区三区在线| 在线看a的网站| 欧美大码av| 三上悠亚av全集在线观看| 午夜亚洲福利在线播放| 一级毛片女人18水好多| 男女下面进入的视频免费午夜 | av视频免费观看在线观看| 成年人黄色毛片网站| netflix在线观看网站| 在线观看免费视频网站a站| 久久九九热精品免费| 热re99久久国产66热| 亚洲欧美日韩无卡精品| 午夜免费激情av| 久久国产亚洲av麻豆专区| 99国产极品粉嫩在线观看| 免费搜索国产男女视频| 精品高清国产在线一区| 另类亚洲欧美激情| 亚洲成国产人片在线观看| 国产精品亚洲一级av第二区| 国产av精品麻豆| √禁漫天堂资源中文www| 不卡一级毛片| 啪啪无遮挡十八禁网站| 亚洲中文日韩欧美视频| 1024香蕉在线观看| 女人被狂操c到高潮| 麻豆成人av在线观看| 久久久国产精品麻豆| 成人亚洲精品av一区二区 | 国产区一区二久久| 亚洲 欧美 日韩 在线 免费| 大型av网站在线播放| 午夜免费鲁丝| 99re在线观看精品视频| 精品久久久久久电影网| 动漫黄色视频在线观看| 免费搜索国产男女视频| 女人爽到高潮嗷嗷叫在线视频| 午夜免费观看网址| 女人被狂操c到高潮| 亚洲中文字幕日韩| 一夜夜www| 淫妇啪啪啪对白视频| 色在线成人网| 99热国产这里只有精品6| 欧美精品啪啪一区二区三区| 亚洲av电影在线进入| 多毛熟女@视频| 欧美+亚洲+日韩+国产| 电影成人av| 中文字幕高清在线视频| avwww免费| 在线观看日韩欧美| 老熟妇乱子伦视频在线观看| 啦啦啦 在线观看视频| 自拍欧美九色日韩亚洲蝌蚪91| 久久婷婷成人综合色麻豆| 欧美日韩乱码在线| 人人妻人人添人人爽欧美一区卜| 一区二区日韩欧美中文字幕| 亚洲成国产人片在线观看| 亚洲精品在线美女| 亚洲七黄色美女视频| xxxhd国产人妻xxx| 国产一卡二卡三卡精品| 97超级碰碰碰精品色视频在线观看| 一边摸一边做爽爽视频免费| 国产免费现黄频在线看| 国内久久婷婷六月综合欲色啪| 国产精品免费视频内射| 搡老岳熟女国产| 久久精品人人爽人人爽视色| 人人妻人人澡人人看| 午夜成年电影在线免费观看| 精品卡一卡二卡四卡免费| 国产高清视频在线播放一区| 亚洲av成人av| 男人的好看免费观看在线视频 | 波多野结衣一区麻豆| 国产人伦9x9x在线观看| 午夜激情av网站| 国产xxxxx性猛交| 精品免费久久久久久久清纯| 首页视频小说图片口味搜索| 夜夜看夜夜爽夜夜摸 | 美女扒开内裤让男人捅视频| 人人妻,人人澡人人爽秒播| 久久精品成人免费网站| 亚洲国产欧美网| 一区二区日韩欧美中文字幕| 久久久国产成人精品二区 | 欧美日韩视频精品一区| 99国产精品一区二区三区| 91精品三级在线观看| 欧美成人免费av一区二区三区| 色哟哟哟哟哟哟| 大型av网站在线播放| 中文字幕av电影在线播放| 日韩精品免费视频一区二区三区| 性少妇av在线| 丰满饥渴人妻一区二区三| 天堂中文最新版在线下载| 91老司机精品| 午夜免费观看网址| 老司机福利观看| 波多野结衣高清无吗| 免费看十八禁软件| 中文字幕精品免费在线观看视频| 长腿黑丝高跟| 高清在线国产一区| 天天影视国产精品| aaaaa片日本免费| 成人特级黄色片久久久久久久| 黄色视频,在线免费观看| 久久午夜综合久久蜜桃| 天天影视国产精品| 免费在线观看黄色视频的| 久久国产精品影院| 交换朋友夫妻互换小说| 亚洲一区二区三区不卡视频| 女性生殖器流出的白浆| 91老司机精品| 久久精品国产清高在天天线| 欧美成人免费av一区二区三区| 日本免费一区二区三区高清不卡 | 很黄的视频免费| 国产精品一区二区精品视频观看| 成人亚洲精品一区在线观看| 怎么达到女性高潮| 国产一卡二卡三卡精品| 日本三级黄在线观看| 纯流量卡能插随身wifi吗| 国产黄色免费在线视频| 岛国在线观看网站| 国产伦人伦偷精品视频| 亚洲中文日韩欧美视频| 五月开心婷婷网| 国内久久婷婷六月综合欲色啪| 波多野结衣av一区二区av| 人人妻人人澡人人看| 不卡一级毛片| 制服诱惑二区| 丰满饥渴人妻一区二区三| 日韩人妻精品一区2区三区| 亚洲自偷自拍图片 自拍| 久久久国产精品麻豆| 亚洲精品久久午夜乱码| 久久精品影院6| 久久影院123| 国产精品香港三级国产av潘金莲| 婷婷丁香在线五月| 亚洲国产精品sss在线观看 | 夜夜看夜夜爽夜夜摸 | 精品久久久精品久久久| 成在线人永久免费视频| 欧美乱码精品一区二区三区| 久久中文字幕一级| 无限看片的www在线观看| 久久久国产精品麻豆| 看免费av毛片| 99在线人妻在线中文字幕| xxx96com| 中文字幕人妻丝袜一区二区| 精品久久久久久久久久免费视频 | www国产在线视频色| 99久久人妻综合| 99香蕉大伊视频| 亚洲一区二区三区色噜噜 | 久久久久国产精品人妻aⅴ院| 嫩草影院精品99| 在线观看免费高清a一片| 国产一区二区三区综合在线观看| 99精品在免费线老司机午夜| 国产三级黄色录像| 美女福利国产在线| 精品久久久久久久毛片微露脸| 丁香六月欧美| av有码第一页| 亚洲av片天天在线观看| av在线天堂中文字幕 | 岛国视频午夜一区免费看| 亚洲欧洲精品一区二区精品久久久| 亚洲国产看品久久| 国产激情久久老熟女| 在线视频色国产色| 欧美一级毛片孕妇| 亚洲国产看品久久| 夜夜夜夜夜久久久久| 少妇 在线观看| 亚洲国产精品一区二区三区在线| 久久精品亚洲精品国产色婷小说| 99国产精品免费福利视频| 婷婷丁香在线五月| 久久亚洲精品不卡| 天堂影院成人在线观看| 午夜福利,免费看| 最近最新中文字幕大全电影3 | 国产精品免费视频内射| 日韩大码丰满熟妇| 久久久久久免费高清国产稀缺| 大香蕉久久成人网| 国产成人欧美| 久99久视频精品免费| 国产精品综合久久久久久久免费 | 欧美中文日本在线观看视频| 在线视频色国产色| 欧美日韩亚洲国产一区二区在线观看| 国产精品久久电影中文字幕| 男人舔女人下体高潮全视频| 欧美中文综合在线视频| 1024香蕉在线观看| 人人妻人人添人人爽欧美一区卜| 啦啦啦 在线观看视频| 欧美最黄视频在线播放免费 | 免费av中文字幕在线| 男女做爰动态图高潮gif福利片 | 免费观看精品视频网站| 国产精品日韩av在线免费观看 | 精品电影一区二区在线| 男人操女人黄网站| 999久久久国产精品视频| 一级作爱视频免费观看| 欧美日韩精品网址| 叶爱在线成人免费视频播放| www.精华液| 日本五十路高清| 国产高清激情床上av| 国产午夜精品久久久久久| 国产亚洲欧美精品永久| 国产欧美日韩一区二区三区在线| 成人免费观看视频高清| 精品第一国产精品| 无遮挡黄片免费观看| 黄色片一级片一级黄色片| 又紧又爽又黄一区二区| 99国产精品免费福利视频| 色综合欧美亚洲国产小说| 老司机靠b影院| 免费少妇av软件| 国产精品 国内视频| 一级毛片高清免费大全| 免费少妇av软件| 日本一区二区免费在线视频| bbb黄色大片| 亚洲色图av天堂| 国产av精品麻豆| 亚洲情色 制服丝袜| 精品一区二区三卡| 美女 人体艺术 gogo| 亚洲色图av天堂| 美女高潮到喷水免费观看| 在线观看免费高清a一片| 免费高清在线观看日韩| 在线十欧美十亚洲十日本专区| 人成视频在线观看免费观看| 亚洲三区欧美一区| av福利片在线| 村上凉子中文字幕在线| 成熟少妇高潮喷水视频| 国产一卡二卡三卡精品| 中文字幕av电影在线播放| 亚洲av电影在线进入| 国产伦一二天堂av在线观看| 亚洲国产精品一区二区三区在线| 又紧又爽又黄一区二区| 麻豆国产av国片精品| 嫩草影视91久久| 日本vs欧美在线观看视频| ponron亚洲| 热99re8久久精品国产| 男女午夜视频在线观看| 亚洲国产中文字幕在线视频| 亚洲av美国av| 美女福利国产在线| 一夜夜www| 黄色成人免费大全| 69精品国产乱码久久久| 一级a爱视频在线免费观看| 十八禁人妻一区二区| 悠悠久久av| 极品人妻少妇av视频| 天天躁狠狠躁夜夜躁狠狠躁| 丰满人妻熟妇乱又伦精品不卡| 欧美老熟妇乱子伦牲交| 欧美最黄视频在线播放免费 | e午夜精品久久久久久久| 国产又爽黄色视频| 91大片在线观看| 日韩三级视频一区二区三区| 成人永久免费在线观看视频| 一级,二级,三级黄色视频| 亚洲精品国产区一区二| 日韩大码丰满熟妇| 国产一区二区三区视频了| 热99re8久久精品国产| 国产成人系列免费观看| 国产高清国产精品国产三级| 啦啦啦 在线观看视频| 美国免费a级毛片| 久久久久久久久久久久大奶| 老汉色∧v一级毛片| 制服诱惑二区| 91成人精品电影| 久久久国产一区二区| 日韩欧美三级三区| 国产亚洲精品综合一区在线观看 | 黄色成人免费大全| 别揉我奶头~嗯~啊~动态视频| 黑人巨大精品欧美一区二区蜜桃| 久久久国产一区二区| 免费在线观看完整版高清| 精品高清国产在线一区| 国产成人精品无人区| 久久精品91蜜桃| 久久久精品国产亚洲av高清涩受| av欧美777| 久久人人爽av亚洲精品天堂| 露出奶头的视频| 欧美激情久久久久久爽电影 | 国产高清videossex| 亚洲精品美女久久久久99蜜臀| 午夜91福利影院| 一级片免费观看大全| 亚洲国产欧美日韩在线播放| 国产单亲对白刺激| a级片在线免费高清观看视频| 男男h啪啪无遮挡| 男女下面插进去视频免费观看| 精品国产超薄肉色丝袜足j| 精品一区二区三区四区五区乱码| 精品一品国产午夜福利视频| 亚洲色图综合在线观看| 狠狠狠狠99中文字幕| 亚洲 欧美 日韩 在线 免费| 两人在一起打扑克的视频| 国产av一区二区精品久久| 免费观看精品视频网站| 天堂中文最新版在线下载| 亚洲成人免费电影在线观看| 色婷婷av一区二区三区视频| 国产精品国产av在线观看| 国产精品野战在线观看 | 久久久久久免费高清国产稀缺| 老司机午夜十八禁免费视频| 黄色女人牲交| 99国产精品99久久久久| 久久亚洲真实| 精品电影一区二区在线| 亚洲男人的天堂狠狠| 亚洲熟妇中文字幕五十中出 | 十八禁人妻一区二区| 波多野结衣高清无吗| 日韩欧美在线二视频| 国产一区二区在线av高清观看| 又黄又粗又硬又大视频| 大香蕉久久成人网| 久久久国产欧美日韩av| 两个人看的免费小视频| 19禁男女啪啪无遮挡网站| 色婷婷久久久亚洲欧美| 久9热在线精品视频| 巨乳人妻的诱惑在线观看| 高潮久久久久久久久久久不卡| 中文字幕人妻丝袜制服| 妹子高潮喷水视频| 在线av久久热| 午夜福利,免费看| av电影中文网址| 男人的好看免费观看在线视频 | 色综合欧美亚洲国产小说| 中文字幕人妻丝袜一区二区| 日韩国内少妇激情av| 国产精品偷伦视频观看了| 色在线成人网| 黄色a级毛片大全视频| 日本免费a在线| 亚洲三区欧美一区| 女人被狂操c到高潮| 国产成年人精品一区二区 | 久久久久九九精品影院| 国产av在哪里看| 正在播放国产对白刺激| 成在线人永久免费视频| 黄网站色视频无遮挡免费观看| 两人在一起打扑克的视频| 黄片小视频在线播放| av电影中文网址| 欧美精品一区二区免费开放| 日本欧美视频一区| 一级毛片女人18水好多| 久久久久久久精品吃奶| 亚洲 国产 在线| www.熟女人妻精品国产| 大陆偷拍与自拍| 国产视频一区二区在线看| 夜夜夜夜夜久久久久| 岛国视频午夜一区免费看| 国产精品久久久久成人av| 成人黄色视频免费在线看| 巨乳人妻的诱惑在线观看| 窝窝影院91人妻| 亚洲五月天丁香| 日韩精品青青久久久久久| 国产高清videossex| 叶爱在线成人免费视频播放| 欧美日韩黄片免| 人妻久久中文字幕网| 琪琪午夜伦伦电影理论片6080| 国产精品99久久99久久久不卡| 18禁黄网站禁片午夜丰满| 免费av毛片视频| 精品久久久精品久久久| 欧美成狂野欧美在线观看| 精品一区二区三卡| 一区二区三区国产精品乱码| 久久精品91无色码中文字幕| av天堂在线播放| 淫妇啪啪啪对白视频| 欧美在线一区亚洲| 亚洲伊人色综图| 成人18禁高潮啪啪吃奶动态图| 性色av乱码一区二区三区2| 国产高清视频在线播放一区| www.熟女人妻精品国产| 少妇裸体淫交视频免费看高清 | 亚洲黑人精品在线| 亚洲精品在线观看二区| 精品久久久久久久久久免费视频 | 9191精品国产免费久久| 国产色视频综合| 日韩精品免费视频一区二区三区| 色播在线永久视频| 两性夫妻黄色片| av在线播放免费不卡| 亚洲av片天天在线观看| 欧美色视频一区免费| 一a级毛片在线观看| 亚洲国产欧美网| 成年人黄色毛片网站| 在线观看免费视频网站a站| 久久精品国产综合久久久| 91国产中文字幕| 午夜a级毛片| 亚洲午夜理论影院| 后天国语完整版免费观看| 一a级毛片在线观看| 久久精品国产综合久久久| 欧美色视频一区免费| 黄色女人牲交| 两性午夜刺激爽爽歪歪视频在线观看 |