In ultrarelativistic heavy-ion collisions, enormous magnetic fields are generated because of fast-moving charged particles. In the presence of these magnetic fields, the spin of particles is aligned either in the parallel or in the antiparallel direction with respect to the direction of the magnetic field. A finite magnetization is thus produced. It is known that a finite magnetic susceptibility, $chi_{m}$, changes the evolution of the energy density of the quark-gluon plasma (QGP), which is believed to be created in these collisions. Depending on whether the system under consideration is a paramagnetic ($chi_{m}>0$) or diamagnetic ($chi_{m}<0$) fluid, it slows down or speeds up the decay of the energy density, and affects other thermodynamic quantities. In general, one expects that the magnetic susceptibility depends on the magnetic field and temperature. Bearing in mind that these parameters evolve with the evolution of the fluid, a nonuniform magnetic susceptibility in this system is thus expected. In this work, we first determine $chi_{m}$ by using a certain analogy to the standard anisotropic kinetic theory, where the one-particle distribution function is replaced by the corresponding anisotropic distribution function. We then determine the proper time dependence of the magnetic susceptibility in the framework of the ideal transverse magnetohydrodynamics. We also study the effect of dissipation on the evolution of $chi_{m}$.
{"title":"Proper time evolution of magnetic susceptibility in amagnetized plasma of quarks and gluons","authors":"S. Tabatabaee, N. Sadooghi","doi":"10.22323/1.336.0259","DOIUrl":"https://doi.org/10.22323/1.336.0259","url":null,"abstract":"In ultrarelativistic heavy-ion collisions, enormous magnetic fields are generated because of fast-moving charged particles. In the presence of these magnetic fields, the spin of particles is aligned either in the parallel or in the antiparallel direction with respect to the direction of the magnetic field. A finite magnetization is thus produced. It is known that a finite magnetic susceptibility, $chi_{m}$, changes the evolution of the energy density of the quark-gluon plasma (QGP), which is believed to be created in these collisions. Depending on whether the system under consideration is a paramagnetic ($chi_{m}>0$) or diamagnetic ($chi_{m}<0$) fluid, it slows down or speeds up the decay of the energy density, and affects other thermodynamic quantities. In general, one expects that the magnetic susceptibility depends on the magnetic field and temperature. Bearing in mind that these parameters evolve with the evolution of the fluid, a nonuniform magnetic susceptibility in this system is thus expected. In this work, we first determine $chi_{m}$ by using a certain analogy to the standard anisotropic kinetic theory, where the one-particle distribution function is replaced by the corresponding anisotropic distribution function. We then determine the proper time dependence of the magnetic susceptibility in the framework of the ideal transverse magnetohydrodynamics. We also study the effect of dissipation on the evolution of $chi_{m}$.","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115290423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Transport in Dense Nuclear Matter","authors":"Stephan Stetina","doi":"10.22323/1.336.0216","DOIUrl":"https://doi.org/10.22323/1.336.0216","url":null,"abstract":"","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115355164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The qqss and qqcc JPC = 1−− systems are investigated by a quark hadron hybrid model, where the 14 relevant two-meson channels are coupled, while the quark degrees of freedom appear in the short range region. In each of the qqss and qqcc systems, one or more poles have been found. For the qqcc, a pole with a very narrow width appears very close to the ωχc1 threshold, which is also close to the DD1 and DD1 thresholds. There are two poles in the qqss, both of which have a rather larger width. We argue that they can be seeds of the observed exotic mesons like the Y (4260).
{"title":"On the origin of Y(4260) and the $J^{PC}=1^{--}$ exotic mesons","authors":"S. Takeuchi, M. Takizawa","doi":"10.22323/1.336.0131","DOIUrl":"https://doi.org/10.22323/1.336.0131","url":null,"abstract":"The qqss and qqcc JPC = 1−− systems are investigated by a quark hadron hybrid model, where the 14 relevant two-meson channels are coupled, while the quark degrees of freedom appear in the short range region. In each of the qqss and qqcc systems, one or more poles have been found. For the qqcc, a pole with a very narrow width appears very close to the ωχc1 threshold, which is also close to the DD1 and DD1 thresholds. There are two poles in the qqss, both of which have a rather larger width. We argue that they can be seeds of the observed exotic mesons like the Y (4260).","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127071526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the absence of a transverse expansion with respect to the beam direction, the Bjorken flow is unable to describe certain observables in heavy ion collisions. This caveat has motivated the introduction of analytical relativistic hydrodynamics (RH) solutions with transverse expansion, in particular, the 3+1 self-similar (SSF) and Gubser flows. Inspired by recent generalizations of the Bjorken flow to the relativistic magnetohydrodynamics (RMHD), we present a procedure for a generalization of RH solutions to RMHD. Our method is mainly based on symmetry arguments. Using this method, we find the relation between RH degrees of freedom and the magnetic field evolution in the ideal limit for an infinitely conductive fluid, and determine the proper time dependence of the magnetic field in aforementioned flows. In the case of SSF, a family of solutions are found that are related through a certain differential equation. To find the magnetic field evolution in the Gubser flow, we solve RMHD equations for a stationary fluid in a conformally flat $dS^3times E^1$ spacetime. The result is then Weyl transformed back into the Minkowski spacetime. In this case, the temporal evolution of the magnetic field exhibits a transmission between $1/t$ to $1/t^3$ near the center of the collision. The longitudinal component of the magnetic field is found to be sensitive to the transverse size of the fluid. We also find the radial evolution of the magnetic field for both flows. The radial domain of validity in the case of SSF is highly restricted, in contrast to the Gubser flow. A comparison of the results suggests that the Gubser RMHD may give a more appropriate qualitative picture of the magnetic field decay in the quark-gluon plasma (QGP).
{"title":"Evolution of magnetic fields in a transversely expanding highly conductive fluid","authors":"M. Shokri, N. Sadooghi","doi":"10.22323/1.336.0162","DOIUrl":"https://doi.org/10.22323/1.336.0162","url":null,"abstract":"Due to the absence of a transverse expansion with respect to the beam direction, the Bjorken flow is unable to describe certain observables in heavy ion collisions. This caveat has motivated the introduction of analytical relativistic hydrodynamics (RH) solutions with transverse expansion, in particular, the 3+1 self-similar (SSF) and Gubser flows. Inspired by recent generalizations of the Bjorken flow to the relativistic magnetohydrodynamics (RMHD), we present a procedure for a generalization of RH solutions to RMHD. Our method is mainly based on symmetry arguments. Using this method, we find the relation between RH degrees of freedom and the magnetic field evolution in the ideal limit for an infinitely conductive fluid, and determine the proper time dependence of the magnetic field in aforementioned flows. In the case of SSF, a family of solutions are found that are related through a certain differential equation. To find the magnetic field evolution in the Gubser flow, we solve RMHD equations for a stationary fluid in a conformally flat $dS^3times E^1$ spacetime. The result is then Weyl transformed back into the Minkowski spacetime. In this case, the temporal evolution of the magnetic field exhibits a transmission between $1/t$ to $1/t^3$ near the center of the collision. The longitudinal component of the magnetic field is found to be sensitive to the transverse size of the fluid. We also find the radial evolution of the magnetic field for both flows. The radial domain of validity in the case of SSF is highly restricted, in contrast to the Gubser flow. A comparison of the results suggests that the Gubser RMHD may give a more appropriate qualitative picture of the magnetic field decay in the quark-gluon plasma (QGP).","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116011684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matthias Warschinke, Ryutaro Matsudo, Shogo Nishino, T. Shinohara, K. Kondo
{"title":"Composite operator and condensate in SU(N) Yang-Mills theory with U(N-1) stability group","authors":"Matthias Warschinke, Ryutaro Matsudo, Shogo Nishino, T. Shinohara, K. Kondo","doi":"10.22323/1.336.0066","DOIUrl":"https://doi.org/10.22323/1.336.0066","url":null,"abstract":"","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122559670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Different situations in HEP data analysis involve the calculation of confidence intervals for quantities derived as linear combinations of observations that follow a Poisson law. Although apparently a simple problem, no precise methods exist when asymptotic approximations are not accurate. Existing procedures are reviewed, and new approaches are proposed. Their performance and range of validity is checked in different benchmarks. In general, the simple methods based on error propagation or application of Wilks theorem to MLE show important undercoverage or overcoverage for low number of counts. On the contrary, methods based in profiling the likelihood or projecting the multidimensional confidence regions obtained with the Neyman construction show a much better performance. XIII Quark Confinement and the Hadron Spectrum Confinement2018 31 July 6 August 2018 Maynooth University, Ireland
{"title":"Confidence intervals for linear combinations of Poisson observations","authors":"F. Matorras","doi":"10.22323/1.336.0240","DOIUrl":"https://doi.org/10.22323/1.336.0240","url":null,"abstract":"Different situations in HEP data analysis involve the calculation of confidence intervals for quantities derived as linear combinations of observations that follow a Poisson law. Although apparently a simple problem, no precise methods exist when asymptotic approximations are not accurate. Existing procedures are reviewed, and new approaches are proposed. Their performance and range of validity is checked in different benchmarks. In general, the simple methods based on error propagation or application of Wilks theorem to MLE show important undercoverage or overcoverage for low number of counts. On the contrary, methods based in profiling the likelihood or projecting the multidimensional confidence regions obtained with the Neyman construction show a much better performance. XIII Quark Confinement and the Hadron Spectrum Confinement2018 31 July 6 August 2018 Maynooth University, Ireland","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133973227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fractal structure, power-law distribution and hadron spectrum","authors":"A. Deppman","doi":"10.22323/1.336.0072","DOIUrl":"https://doi.org/10.22323/1.336.0072","url":null,"abstract":"","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114729442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"XYZ States at BESIII","authors":"L. Koch","doi":"10.22323/1.336.0109","DOIUrl":"https://doi.org/10.22323/1.336.0109","url":null,"abstract":"","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123611663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Born-Oppenheimer approximation is the standard method for the studying atoms and molecules. It is founded on the observation that the energy scale of the electron dynamics in a molecule is larger than that of the nuclei. A very similar physical picture can be used to describe QCD states containing heavy quarks as well as light quarks and gluonic excitations. In this communication I present selected results of a recent work [N. Brambilla, G. Krein, J. Tarrús-Castellà and A. Vairo, Phys. Rev. D 97, 016016 (2018)] in which the Born-Oppenheimer approximation for atomic and hadronic molecular systems emerges as the leading-order approximation of an effective field theory obtained by sequentially integrating out degrees of freedom living at energies above the typical energy scale where the dynamics of the heavy degrees of freedom occurs. As an example, the simple case of a ion molecule formed by two heavy nuclei and one electron is considered.
玻恩-奥本海默近似法是研究原子和分子的标准方法。它建立在观察到分子中电子动力学的能量尺度大于原子核的能量尺度的基础上。一个非常相似的物理图像可以用来描述含有重夸克、轻夸克和胶子激发的QCD态。在这篇文章中，我介绍了最近一项研究[N。Brambilla, G. Krein, J. Tarrús-Castellà和A. Vairo，物理学家。其中，原子和强子分子系统的Born-Oppenheimer近似作为有效场论的阶近似出现，该有效场论是通过对生活在重自由度动力学发生的典型能量尺度以上的自由度进行顺序积分获得的。作为一个例子，我们考虑了由两个重原子核和一个电子构成的离子分子的简单情况。
{"title":"The Born-Oppenheimer approximation in an effective field theory framework","authors":"G. Krein","doi":"10.22323/1.336.0110","DOIUrl":"https://doi.org/10.22323/1.336.0110","url":null,"abstract":"The Born-Oppenheimer approximation is the standard method for the studying atoms and molecules. It is founded on the observation that the energy scale of the electron dynamics in a molecule is larger than that of the nuclei. A very similar physical picture can be used to describe QCD states containing heavy quarks as well as light quarks and gluonic excitations. In this communication I present selected results of a recent work [N. Brambilla, G. Krein, J. Tarrús-Castellà and A. Vairo, Phys. Rev. D 97, 016016 (2018)] in which the Born-Oppenheimer approximation for atomic and hadronic molecular systems emerges as the leading-order approximation of an effective field theory obtained by sequentially integrating out degrees of freedom living at energies above the typical energy scale where the dynamics of the heavy degrees of freedom occurs. As an example, the simple case of a ion molecule formed by two heavy nuclei and one electron is considered.","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116460309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The plans for the second Run of the LHC changes the focus in the Higgs sector from searches to precision measurements. Effective Lagrangians can be used for parameterisation. A signal morphing method is developed to take all parameters into account simultaneously and model interference effects. It provides a continues description of arbitrary physical signal observables such as cross sections or differential distributions in a multidimensional space of coupling parameters. This method is capable of morphing signal distributions and rates based on a minimal orthogonal set of independent base samples and therefore allows to directly fit the coupling parameters that describe the Standard Model and possible non-Standard Model interactions for, for example, the Higgs boson.
{"title":"Continuous signal modelling in a multidimensional space of coupling parameters","authors":"L. Brenner","doi":"10.22323/1.336.0228","DOIUrl":"https://doi.org/10.22323/1.336.0228","url":null,"abstract":"The plans for the second Run of the LHC changes the focus in the Higgs sector from searches to precision measurements. Effective Lagrangians can be used for parameterisation. A signal morphing method is developed to take all parameters into account simultaneously and model interference effects. It provides a continues description of arbitrary physical signal observables such as cross sections or differential distributions in a multidimensional space of coupling parameters. This method is capable of morphing signal distributions and rates based on a minimal orthogonal set of independent base samples and therefore allows to directly fit the coupling parameters that describe the Standard Model and possible non-Standard Model interactions for, for example, the Higgs boson.","PeriodicalId":441384,"journal":{"name":"Proceedings of XIII Quark Confinement and the Hadron Spectrum — PoS(Confinement2018)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127677819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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