393 research outputs found
Extending the LHC Reach for New Physics with Sub-Millimeter Displaced Vertices
Particles with a sub-millimeter decay length appear in many models of physics
beyond the Standard Model. However, their longevity has been often ignored in
their LHC searches and they have been regarded as promptly-decaying particles.
In this letter, we show that, by requiring displaced vertices on top of the
event selection criteria used in the ordinary search strategies for
promptly-decaying particles, we can considerably extend the LHC reach for
particles with a decay length of . We discuss a way of
reconstructing sub-millimeter displaced vertices by exploiting the same
technique used for the primary vertex reconstruction on the assumption that the
metastable particles are always pair-produced and their decay products contain
high- jets. We show that, by applying a cut based on displaced
vertices on top of standard kinematical cuts for the search of new particles,
the LHC reach can be significantly extended if the decay length is . In addition, we may measure the lifetime of the target
particle through the reconstruction of displaced vertices, which plays an
important role in understanding the new physics behind the metastable
particles.Comment: 18 pages, 6 figure
Momentum-Dependent Hybridization Gap and dispersive in-gap state of The Kondo Semiconductor SmB6
We report the temperature-dependent three-dimensional angle-resolved
photoemission spectra of the Kondo semiconductor SmB. We found a difference
in the temperature dependence of the peaks at the X and points, due to
hybridization between the Sm 5d conduction band and the nearly localized Sm 4f
state. The peak intensity at the X point has the same temperature dependence as
the valence transition below 120 K, while that at the point is
consistent with the magnetic excitation at Q=(0.5,0.5,0.5) below 30 K. This
suggests that the hybridization with the valence transition mainly occurs at
the X point, and the initial state of the magnetic excitation is located at the
point.Comment: 5 pages, 3 figure
Searching for Metastable Particles with Sub-Millimeter Displaced Vertices at Hadron Colliders
A variety of new-physics models predict metastable particles whose decay
length is mm. Conventional displaced-vertex searches are less
sensitive to this sub-millimeter decay range, and thus such metastable
particles have been looked for only in usual prompt decay searches. In this
paper, we show that an additional event-selection cut based on the vertex
reconstruction using charged tracks considerably improves the sensitivity of
ordinary searches which rely only on kinematic selection criteria, for
particles with a decay length of . To that end, we
consider a metastable gluino as an example, and study the impact of this new
event-selection cut on gluino searches at the LHC by simulating both the signal
and Standard Model background processes. Uncertainty of the displaced-vertex
reconstruction due to the limited resolution of track reconstruction is taken
into account. We also discuss possibilities for optimization of the kinematic
selection criteria, which takes advantage of significant reduction of
background through the requirement of displaced vertices. In addition, we
demonstrate that using the method discussed in this paper it is possible to
measure the lifetime of metastable particles with an accuracy at
the high-luminosity LHC. Implications for a future 100 TeV collider are also
studied, where produced particles tend to be more boosted and thus it is easier
to detect the longevity of metastable particles.Comment: 55 pages, 24 figure
A Robust Formation Control Strategy for Multi-Agent Systems with Uncertainties via Adaptive Gain Robust Controllers
This paper deals with a design problem of an adaptive gain robust controller which achieves consensus for multi-agent system (MAS) with uncertainties. In the proposed controller design approach, the relative position between the leader and followers are considered explicitly, and the proposed adaptive gain robust controller consisting of fixed gains and variable ones tuned by time-varying adjustable parameters can reduce the effect of uncertainties. In this paper, we show that sufficient conditions for the existence of the proposed adaptive gain robust controller are reduced to solvability of linear matrix inequalities (LMIs). Finally, the effectiveness of the proposed robust formation control system is verified by simple numerical simulations. A main result of this study is that the proposed adaptive gain robust controller can achieve consensus and formation control giving consideration to relative distance in spite of uncertainties
Synthesis of Formation Control Systems for Multi-Agent Systems under Control Gain Perturbations
This paper proposed a linear matrix inequality (LMI)-based design method of non-fragile guaranteed cost controllers for multi-agent systems (MASs) with leader-follower structures. In the guaranteed cost control approach, the resultant controller guarantees an upper bound on the given cost function together with asymptotical stability for the closed-loop system. The proposed non-fragile guaranteed cost control system can achieve consensus for MASs despite control gain perturbations. The goal is to develop an LMI-based sufficient condition for the existence of the proposed non-fragile guaranteed cost controller. Moreover, a design problem of an optimal non-fragile guaranteed cost controller showe that minimizing an upper bound on the given quadratic cost function can be reduced to constrain a convex optimization problem. Finally, numerical examples were given to illustrate the effectiveness of the proposed non-fragile controller for MASs
Novel Heterogenous CHS1 Mutations Identified in Five Japanese Patients with Chediak-Higashi Syndrome
Chediak-Higashi syndrome (CHS) is a rare, autosomal recessive disorder characterized by oculocutaneous albinism, recurrent bacterial infections and progressive neurological dysfunction. We demonstrate novel heterogenous mutations of CHS1, the responsive gene of CHS, identified in five Japanese patients with CHS. Patients 1, 2, and 3 were siblings, and they had albinism of the skin and hair. They all had a heterogenous two-base deletion (c.5541-5542 del AA, p.Q1847fsX1850) in exon 18. Patient 4 had a heterogenous single-base insertion (c.3944-3945 ins C, p.T1315fsX1331) in exon 10. The patient exhibited severe early-onset phenotype and suffered from hemophagocytic lymphohistiocytosis. Patient 5 had two heterogenous nonsense mutations; c.7982C>G, p.S2661X in exon 30 and c.8281A>T, p.R2761X in exon 31. The patient suffered from infections in childhood and had visual disturbance and albinism of the skin and hair. The CHS1 mutations described here have not been reported previously
Specific Serum-free Conditions can Differentiate Mouse Embryonic Stem Cells into Osteochondrogenic and Myogenic Progenitors.
Exact location of the multicritical point for finite-dimensional spin glasses: A conjecture
We present a conjecture on the exact location of the multicritical point in
the phase diagram of spin glass models in finite dimensions. By generalizing
our previous work, we combine duality and gauge symmetry for replicated random
systems to derive formulas which make it possible to understand all the
relevant available numerical results in a unified way. The method applies to
non-self-dual lattices as well as to self dual cases, in the former case of
which we derive a relation for a pair of values of multicritical points for
mutually dual lattices. The examples include the +-J and Gaussian Ising spin
glasses on the square, hexagonal and triangular lattices, the Potts and Z_q
models with chiral randomness on these lattices, and the three-dimensional +-J
Ising spin glass and the random plaquette gauge model.Comment: 27 pages, 3 figure
Investigation of the correlation between the electrical contact resistance and the contact area of mechanical lap joint fabricated with high-temperature superconducting tapes using X-ray microtomography
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