14,539 research outputs found

    Study of the slepton non-universality at the CERN Large Hadron Collider

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    In supersymmetric theory, the sfermion-fermion-gaugino interactions conserve the chirality of (s)fermions. The effect appears as the charge asymmetry in m(jl)m(jl) distributions at the CERN Large Hadron Collider where jets and leptons arise from the cascade decay q~qχ~20qll~\tilde{q} \to q \tilde{\chi}^0_2 \to ql\tilde{l}. Furthermore, the decay branching ratios and the charge asymmetries in m(jl)m(jl) distributions are flavor non-universal due to the l~L\tilde{l}_L and l~R\tilde{l}_R mixing. When tanβ\tan\beta is large, the non-universality between ee and μ\mu becomes O(10)O(10)% level. We perform a Monte Carlo simulation for some minimal supergravity benchmark points to demonstrate the detectability.Comment: 19 pages, 6 figures, revte

    NMR relaxation of quantum spin chains in magnetic fields

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    We investigate NMR relaxation rates 1/T_1 of quantum spin chains in magnetic fields. Universal properties for the divergence behavior of 1/T_1 are obtained in the Tomonaga-Luttinger-liquid state. The results are discussed in comparison with experimental results.Comment: 5 pages, 3 figure

    Environmental dependence of 8um luminosity functions of galaxies at z~0.8: Comparison between RXJ1716.4+6708 and the AKARI NEP deep field

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    We aim to reveal environmental dependence of infrared luminosity functions (IR LFs) of galaxies at z~0.8 using the AKARI satellite. We construct restframe 8um IR LFs in the cluster region RXJ1716.4+6708 at z=0.81, and compare them with a blank field using the AKARI North Ecliptic Pole deep field data at the same redshift. AKARI's wide field of view (10'x10') is suitable to investigate wide range of galaxy environments. AKARI's 15um filter is advantageous here since it directly probes restframe 8um at z~0.8, without relying on a large extrapolation based on a SED fit, which was the largest uncertainty in previous work. We have found that cluster IR LFs at restframe 8um have a factor of 2.4 smaller L^* and a steeper faint-end slope than that of the field. Confirming this trend, we also found that faint-end slopes of the cluster LFs becomes flatter and flatter with decreasing local galaxy density. These changes in LFs cannot be explained by a simple infall of field galaxy population into a cluster. Physics that can preferentially suppress IR luminous galaxies in high density regions is required to explain the observed results.Comment: Accepted for publication in A&A AKARI special issu

    Muon spin relaxation and rotation study on the solid solution of the two spin-gap systems (CH3)2CHNH3-CuCl3 and (CH3)2CHNH3-CuBr3

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    Muon-spin-rotation and relaxation studies have been performed on (CH3_3)2_2CHNH3_3Cu(Clx_xBr1x_{1-x})3_3 with xx=0.85 and 0.95, which are solid solutions of the two isomorphic spin-gap systems (CH3_3)2_2CHNH3_3CuCl3_3 and (CH3_3)2_2CHNH3_3CuBr3_3 with different spin gaps. The sample with xx=0.85 showed a clear muon spin rotation under zero-field below TNT_{\rm N}=11.65K, indicating the existence of a long-range antiferromagnetic order. A critical exponent of the hyperfine field was obtained to be β\beta=0.33, which agrees with 3D-Ising model. In the other sample with xx=0.95, an anomalous enhancement of the muon spin relaxation was observed at very low temperatures indicating a critical slowing down due to a magnetic instability of the ground state