著者

原 和彦 金 信弘 大川 英希 佐藤 構二 受川 史彦 ATLAS Collaboration Hara K. Kim S.H. Okawa H. Sato K. Ukegawa F.

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2018, no.6, 2018-06

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This paper presents a search for direct electroweak gaugino or gluino pair production with a chargino nearly mass-degenerate with a stable neutralino. It is based on an integrated luminosity of 36.1 fb−1 of pp collisions at s√=13 TeV collected by the ATLAS experiment at the LHC. The final state of interest is a disappearing track accompanied by at least one jet with high transverse momentum from initial-state radiation or by four jets from the gluino decay chain. The use of short track segments reconstructed from the innermost tracking layers significantly improves the sensitivity to short chargino lifetimes. The results are found to be consistent with Standard Model predictions. Exclusion limits are set at 95% confidence level on the mass of charginos and gluinos for different chargino lifetimes. For a pure wino with a lifetime of about 0.2 ns, chargino masses up to 460 GeV are excluded. For the strong production channel, gluino masses up to 1.65 TeV are excluded assuming a chargino mass of 460 GeV and lifetime of 0.2 ns.

著者

Ishibashi Nobuyuki Murakami Koichi

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2013, no.9, pp.53, 2013-09

被引用文献数

9

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We study the multiloop amplitudes of the light-cone gauge closed bosonic string field theory for d ≠ 26. We show that the amplitudes can be recast into a BRST invariant form by adding a nonstandard worldsheet theory for the longitudinal variables X ± andthereparametrizationghostsystem. Theresultsobtainedinthispaperforbosonic strings provide a first step towards the examination whether the dimensional regularization works for the multiloop amplitudes of the light-cone gauge superstring field theory.

著者

Baba Takayuki Ishibashi Nobuyuki

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2013, no.4, pp.50, 2013-04

被引用文献数

15

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For a classical solution

著者

Hatsuda Yasuyuki Ito Katsushi Satoh Yuji

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2013, no.2, pp.67, 2013-02

被引用文献数

9 8

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We study the null-polygonal minimal surfaces in AdS4, which correspond to the gluon scattering amplitudes/Wilson loops in N = 4 super Yang-Mills theory at strong coupling. The area of the minimal surfaces with n cusps is characterized by the thermodynamic Bethe ansatz (TBA) integral equations or the Y-system of the homogeneous sine-Gordon model, which is regarded as the SU(n − 4)4 /U(1) n−5 generalized parafermion theory perturbed by the weight-zero adjoint operators. Based on the relation to the TBA systems of the perturbed W minimal models, we solve the TBA equations by using the conformal perturbation theory, and obtain the analytic expansion of the remainder function around the UV/regular-polygonal limit for n = 6 and 7. We compare the rescaled remainder function for n = 6 with the two-loop one, to observe that they are close to each other similarly to the AdS3 case.

著者

Sakai Kazuhiro Satoh Yuji

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.3, pp.77, 2010-03

被引用文献数

16

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We construct constant mean curvature surfaces of the general finite-gap type in AdS 3. The special case with zero mean curvature gives minimal surfaces relevant for the study of Wilson loops and gluon scattering amplitudes in $ \mathcal{N} = 4 $ super Yang-Mills. We also analyze properties of the finite-gap solutions including asymptotic behavior and the degenerate (soliton) limit, and discuss possible solutions with null boundaries.

著者

Avsar Emil Hatta Yoshitaka Matsuo Toshihiro

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.3, pp.37, 2010-03

被引用文献数

15 5

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Based on the AdS/CFT correspondence, we present a holographic description of various C-odd exchanges in high energy baryon-(anti)baryon scattering, and calculate their respective contributions to the difference in the total cross sections. We show that, due to the warp factor of AdS 5, the single Odderon exchange gives a larger total cross section in baryon-baryon collisions than in baryon-antibaryon collisions at asymptotically high energies.

著者

Hatsuda Yasuyuki Ito Katsushi Sakai Kazuhiro Satoh Yuji

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.4, pp.108, 2010-04

被引用文献数

28 17

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We study classical open string solutions with a null polygonal boundary in AdS 3 in relation to gluon scattering amplitudes in $$ \mathcal{N} = 4 $$ super Yang-Mills at strong coupling. We derive in full detail the set of integral equations governing the decagonal and the dodecagonal solutions and identify them with the thermodynamic Bethe ansatz equations of the homogeneous sine-Gordon models. By evaluating the free energy in the conformal limit we compute the central charges, from which we observe general correspondence between the polygonal solutions in AdS n and generalized parafermions.

著者

Aoki Sinya Balog Janos Weisz Peter

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.5, pp.8, 2010-05

被引用文献数

11 17

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We investigate the short distance behavior of nucleon-nucleon (NN) potentials defined through Bethe-Salpeter wave functions, by perturbatively calculating anomalous dimensions of 6-quark operators in QCD. Thanks to the asymptotic freedom of QCD, 1-loop computations give certain exact results for the potentials in the zero distance limit. In particular the functional form of the S-state central NN potential at short distance r is predicted to be a little weaker than r −2. On the other hand, due to the intriguing character of the anomalous dimension spectrum, perturbative considerations alone can not determine whether this potential is repulsive or attractive at short distances. A crude estimation suggests that the force at short distance is repulsive, as found numerically in lattice QCD. A similar behavior is found for the tensor potential.

著者

Baba Yutaka Ishibashi Nobuyuki Murakami Koichi

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.8, pp.102, 2010-08

被引用文献数

7 5

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We propose a dimensional regularization scheme to deal with the divergences caused by colliding supercurrents inserted at the interaction points, in the light-cone gauge NSR superstring field theory. We formulate the theory in d dimensions and define the amplitudes as analytic functions of d. With an appropriately chosen three-string interaction term and large negative d, the tree level amplitudes for the (NS,NS) closed strings can be recast into a BRST invariant form, using the superconformal field theory proposed in ref. [1]. We show that in the limit d →10 they coincide with the results of the first quantized theory. Therefore we obtain the desired results without adding any contact interaction terms to the action.

著者

Hatsuda Yasuyuki Ito Katsushi Sakai Kazuhiro Satoh Yuji

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2010, no.9, pp.64, 2010-09

被引用文献数

17 14

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We study six-point gluon scattering amplitudes in $$ \mathcal{N} = 4 $$ super Yang-Mills theory at strong coupling by investigating the thermodynamic Bethe ansatz equations of the underlying $$ {\mathbb{Z}_4} $$-symmetric integrable model both analytically and numerically. By the conformal field theory (CFT) perturbation, we compute the free energy part of the remainder function with generic chemical potential near the CFT/small mass limit. Combining this with the expansion of the Y-functions, we obtain the remainder function near the small mass limit up to a function of the chemical potential, which can be evaluated numerically. We also find the leading corrections to the remainder function near the large mass limit. We confirm that these results are in good agreement with numerical computations.

著者

Kimura Taro Komatsu Shota Misumi Tatsuhiro Noumi Toshifumi Torii Shingo Aoki Sinya

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2012, no.1, pp.048, 2012-01

被引用文献数

16

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Employing the spin-flavor representation, we investigate the structures of the doubler-mixing symmetries and the mechanisms of their spontaneous breakdown in four types of lattice fermion formulation. We first revisit the U(4) × U(4) symmetries of the naive fermion with the vanishing bare mass m, and re-express them in terms of the spinflavor representation. We apply the same method to the Wilson fermion, which possesses only the U(1) vector symmetry for general values of m. For a special value of m, however, there emerges an additional U(1) symmetry to be broken by pion condensation. We also explore two types of minimally doubled fermion, and discover a similar kind of symmetry enhancement and its spontaneous breakdown.

著者

Aoki Sinya Balog Janos Weisz Peter

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

no.9, pp.83, 2010-09

被引用文献数

7 13

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The short distance behavior of baryon-baryon potentials defined throughNambu-Bethe-Salpeter wave functions is investigated using the operator product expansion.In a previous analysis of the nucleon-nucleon case, corresponding to the SU(3) channels27s and 10a, we argued that the potentials have a repulsive core. A new feature occursfor the case of baryons made up of three flavors: manifestly asymptotically attractive potentialsappear in the singlet and octet channels. Attraction in the singlet channel wasfirst indicated by quark model considerations, and recently been found in numerical latticesimulations. The latter have however not yet revealed asymptotic attraction in the octetchannels; we give a speculative explanation for this apparent discrepancy.

著者

Ishibashi Nobuyuki Murakami Koichi

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2011, no.1, pp.8, 2011-01

被引用文献数

6 4

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Light-cone gauge superstring theory in noncritical dimensions corresponds to a worldsheet theory with nonstandard longitudinal part in the conformal gauge. The longitudinal part of the worldsheet theory is a superconformal field theory called X ± CFT. We show that the X ± CFT combined with the super-reparametrization ghost system can be described by free variables. It is possible to express the correlation functions in terms of these free variables. Bosonizing the free variables, we construct the spin fields and BRST invariant vertex operators for the Ramond sector in the conformal gauge formulation. By using these vertex operators, we can rewrite the tree amplitudes of the noncritical light-cone gauge string field theory, with external lines in the (R,R) sector as well as those in the (NS,NS) sector, in a BRST invariant way.

著者

Hatta Y. Iancu E. Mueller A. H. Triantafyllopoulos D. N.

出版者

Published for SISSA by Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2011, no.2, pp.065, 2011-02

被引用文献数

19

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We show that a source which radiates in the vacuum of the strongly coupled N = 4=4 SYM theory produces an energy distribution which, in the supergravity approximation, has the same space-time pattern as the corresponding classical distribution: the radiation propagates at the speed of light without broadening. We illustrate this on the basis of several examples: a small perturbation propagating down a steady string, a massless particle falling into AdS5, and the decay of a time-like wave-packet. A similar observation was made in Phys. Rev. D81 (2010) 126001 for the case of a rotating string. In all these cases, the absence of broadening is related to the fact that the energy backreaction on the boundary arises exclusively from the bulk perturbation at, or near, the boundary. This is so since bulk sources which propagate in AdS5 at the speed of light do not generate any energy on the boundary. We interpret these features as an artifact of the supergravity approximation, which fails to encode quantum mechanical fluctuations that should be present even in the strong coupling limit. We argue that such fluctuations should enter the dual string theory as longitudinal string fluctuations, which are not suppressed at strong coupling. We heuristically estimate the effects of such fluctuations and argue that they restore the broadening of the radiation, in agreement with expectations from both quantum mechanics and the ultraviolet/infrared correspondence.

著者

Hatsuda Yasuyuki Ito Katsushi Sakai Kazuhiro Satoh Yuji

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2011, no.4, pp.100, 2011-04

被引用文献数

13

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We study gluon scattering amplitudes/Wilson loops in =4 super Yang-Mills theory at strong coupling by calculating the area of the minimal surfaces in AdS 3 based on the associated thermodynamic Bethe ansatz system. The remainder function of the amplitudes is computed by evaluating the free energy, the T- and Y-functions of the homogeneous sine-Gordon model. Using conformal field theory (CFT) perturbation, we examine the mass corrections to the free energy around the CFT point corresponding to the regular polygonal Wilson loop. Based on the relation between the T-functions and the g-functions, which measure the boundary entropy, we calculate corrections to the T-and Y-functions as well as express them at the CFT point by the modular S-matrix. We evaluate the remainder function around the CFT point for 8 and 10-point amplitudes explicitly and compare these analytic expressions with the 2-loop formulas. The two rescaled remainder functions show very similar power series structures.

著者

Ishibashi Nobuyuki Murakami Koichi

出版者

Springer

雑誌

Journal of high energy physics (ISSN:10298479)

巻号頁・発行日

vol.2011, no.7, pp.90, 2011-07

被引用文献数

3 1

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We consider the dimensional regularization of the light-cone gauge type II superstring field theories in the NSR formalism. In the previous work, we have calculated the tree-level amplitudes with external lines in the (NS, NS) sector using the regularization and shown that the desired results are obtained without introducing contact term interactions. In this work, we study the tree-level amplitudes with external lines in the Ramond sector. In order to deal with them, we propose a worldsheet theory to be used instead of that for the naive dimensional regularization. With the worldsheet theory, we regularize and define the tree-level amplitudes by analytic continuation. We show that the results coincide with those of the first quantized formulation.