安齋千隼, 東北大
3ループQCDポテンシャル等の数値的および解析的評価に用いるアルゴリズム
摂動QCDにおける静的QCDポテンシャルの3ループ輻射補正を求めるための計算手法を説明する。QCDポテンシャルはQCDにおいて基本的な物理量の1つであり、重いqqbar束縛状態の質量などを初め、新しい物理への制限を与える多くの量の計算にも必要である。また、近距離でのポテンシャルの値が摂動的に高精度で求まれば、格子QCD等から得られるより遠距離での値との比較から、¥alpha_Sの値を高精度に決定することなども可能となる。しかし、これらに必要な計算量は膨大で、精度よく決定するためには新たな計算手法の開発が不可欠である。ここではそれらの一部を紹介する。
初めに、値に寄与する数万に及ぶ積分を、積分同士に成立する関係を用いて数十の積分(Master積分)に帰着するための方法を述べる。この部分は原理的には巨大な連立代数方程式を効率よく解くアルゴリズムである。従来PCクラスタ等が必要と考えられていた計算が通常のPCとMathematicaのコードを用いて現実的な時間で実行可能となっており、QCDポテンシャルの計算以外にも広い分野での応用が期待される。
次に、実際に得られた41個のMaster積分の解析的評価について説明する。各積分は運動量積分の後、最終的に¥Gamma関数及びその微分¥psi^(n)の積を含む多重無限和として表現できる。このうち、¥Gammaがcancelした場合の(¥psi^(n)の積および有理式を含む)一般的な無限和を解析的に評価するためのアルゴリズムを開発したので、それについて述べる。
Harald Fritzsch, Ludwig-Maximilians-Universitaet
Composite Weak Bosons at the LHC
The weak bosons are considered as composite systems. The constituents are confined like the quarks in a rho meson. The substructure scale is estimated to be of the order of 0.5 TeV. A new isoscalar neutral weak boson must exist. Its mass should not exceed 1 TeV. Excitations of the weak bosons can be produced at the LHC. The lowest p-wave state is identified with the particle, which might have been observed at the LHC with a mass of 126 GeV. A substructure for the weak bosons implies also a substructure for the leptons and quarks, which should soon be observed at the LHC.
Pascal Naidon, RIKEN
Recent developments in Efimov physics
The Efimov effect is a special three-body binding mechanism occurring in the universal regime of particles interacting with large scattering lengths. This mechanism allows the existence of an infinite number of bound states related to each other by scale invariance. Originally predicted 40 years ago in the context of nuclear physics, it has been investigated experimentally over the last few years with ultracold gases of atoms. In this talk, I will introduce the basic theory of this effect, and present some of its experimental observations, as well as related developments in few-body theory.
Alessandro De Angelis, U Udine / ICRR, U Tokyo
Dark matter and new particles with Cherenkov telescopes
Recent results from very-high energy cosmic gamma-ray experiments are reviewed, with emphasis on fundamental physics and search for new particles. The prospects for next generation detectors, CTA in particular, are outlined.
木村元, Shibaura Institue of Technology
量子力学の原理探求をする意義と最近の進展
量子力学を — アプリオリな数学ではなく — 物理原理に基づき構築する試みを紹介する.これは近年世界的に研究が進められる一方,国内での関心は高いとは言えない.そこで本セミナーの主目的を,物理理論を原理ベースで理解する意義を共有することとする.その上で,量子力学の原理探求の最適な舞台となる「操作主義的な確率論」を説明し,本研究に関する最新の成果を紹介する.
Ryuichiro Kitano, Tohoku University
Higgs mechanism and confinement
We take both phenomenological and theoretical approaches to this hypothesis, and find that the interpretation seems to show interesting consistencies. In particular, one can identify the rho and omega mesons as the magnetic gauge bosons which provide an explanation of the quark confinement via the dual Meissner effect.
Takayasu Sekihara, KEK
Branching ratios of stopped K^- absorption on light nuclei
In this seminar we discuss the branching ratios of stopped K^- absorption on light nuclei in order to clarify the low-energy antikaon-nucleon interaction. We investigate the mesonic (K^- “N” -> pi Y) and non-mesonic (K^- “N N” -> Y N) absorption processes of the stopped K^- -light nucleus systems. Here we consider deuteron and helium-4 as the K^- absorption targets with realistic wave functions for them, and calculate the branching ratios to compare with the experimental results. We also give several theoretical interpretations of the branching ratios, especially from viewpoint of the Lambda(1405) structure.
Takumi Ito, KEK
Supersymmetric Model with Long-lived Stau at the LHC
Supersymmetric extension of standard model of particle physics is an attractive candidate of TeV energy scale new physics, and an important target of the Large Hadron Collider.
So far, several techniques have been proposed to discover the new physics, and to measure properties of new particles.
Importantly, however, the strategy that we should take depends on the event topology, namely, details of the new physics; particle contents, mass spectrum, and so on.
In this talk, we study the case that the lightest superparticle (LSP) is the gravitino, and in this case, the next-to-lightest superparticle (NLSP) may have very long lifetime.
In addition, if the NLSP is charged particle, it may be possible to directly observe a track of the NLSP in the detectors; this is an characteristic event signal of such a model.
We discuss how we can probe the model by utilizing the charged track of NLSP, paying particular attention to the case that NLSP is the stau.
Naoki Yamamoto, University of Washington
Holography and anomaly matching for resonances
We show a new universal relation for triangle anomalies, an “anomaly matching” for resonances, in a class of holographic models of QCD. We argue its possible realization and consequences in real QCD.
Jiro Arafune, National Institution for Academic Degrees and University Evaluation
Relic Neutrino の反射、屈折について