Understanding the nature of the hidden charm pentaquark(like) signals in the LHCb data for Λ0b → J/ψpK− is a central problem of hadron spectroscopy. We propose a scenario completely different from ...previous ones such as hadron molecules and compact pentaquarks. We identify relevant double triangle mechanisms with leading or lower-order singularities. The associated anomalous threshold cusps at the Σ(*)c D(*) thresholds are significantly more singular than the ordinary ones. Then we demonstrate that the double triangle amplitudes reproduce the peak structures of Pc(4312)+ , Pc(4380)+, and Pc(4457)+ in the LHCb data, through an interference with other common mechanisms. Only the Pc(4440)+ peak is due to a resonance with a width and strength significantly smaller than previously estimated. P+c signals are expected in other processes, and the proposed model (partly) explains the current data, such as the GlueX J/ψ photoproduction data with no P+c signals and the LHCb Λ0b → J/ψpπ− data with a possible signal only from Pc(4440)+. In general, the double triangle singularity is now a possible option to interpret resonancelike structures near thresholds.
Hessian of the Ricci-Calabi functional Nakamura, Satoshi
Proceedings of the American Mathematical Society,
03/2019, Letnik:
147, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The Ricci-Calabi functional is a functional on the space of Kähler metrics of Fano manifolds. Its critical points are called generalized Kähler-Einstein metrics. In this article, we show that the ...Hessian of the Ricci-Calabi functional is non-negative at generalized Kähler-Einstein metrics. As its application, we give another proof of a Matsushima type decomposition theorem for holomorphic vector fields, which was originally proved by Mabuchi. We also discuss a relation to the inverse Monge-Ampère flow developed recently by Collins-Hisamoto-Takahashi.
Social skills training, performed by human trainers, is a well-established method for obtaining appropriate skills in social interaction. Previous work automated the process of social skills training ...by developing a dialogue system that teaches social communication skills through interaction with a computer avatar. Even though previous work that simulated social skills training only considered acoustic and linguistic information, human social skills trainers take into account visual and other non-verbal features. In this paper, we create and evaluate a social skills training system that closes this gap by considering the audiovisual features of the smiling ratio and the head pose (yaw and pitch). In addition, the previous system was only tested with graduate students; in this paper, we applied our system to children or young adults with autism spectrum disorders. For our experimental evaluation, we recruited 18 members from the general population and 10 people with autism spectrum disorders and gave them our proposed multimodal system to use. An experienced human social skills trainer rated the social skills of the users. We evaluated the system's effectiveness by comparing pre- and post-training scores and identified significant improvement in their social skills using our proposed multimodal system. Computer-based social skills training is useful for people who experience social difficulties. Such a system can be used by teachers, therapists, and social skills trainers for rehabilitation and the supplemental use of human-based training anywhere and anytime.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The LHCb data on B+→J/ψϕK+ show four peaks and three dips in the J/ψϕ invariant mass distribution, and the peaks are interpreted as X(4140), X(4274), X(4500) and X(4685)/X(4700) resonance ...contributions. Interestingly, all the peaks and dips are located at (or close to) Ds⁎D¯s(⁎), Ds0⁎(2317)D¯s(⁎), Ds1(2536)D¯s(⁎), and ψ′ϕ thresholds. These coincidences suggest a close connection between the structures and the thresholds, which however has not been seriously considered in previous theoretical studies on the X structures. In fact, if we utilize this connection and interpret the X structures as common s-wave threshold cusps, we face a difficulty: X(4274) and X(4500) have spin-parity that conflict with the experimentally determined ones. In this work, we introduce double triangle mechanisms that cause threshold cusps significantly sharper than the ordinary one-loop ones of the same spin-parity. We demonstrate that all the X and dip structures are well described by a combination of one-loop and double-triangle threshold cusps, thereby proposing a novel interpretation of the X and dip structures.
Osteocytes function as critical regulators of bone homeostasis by coordinating the functions of osteoblasts and osteoclasts, and are constantly exposed to mechanical force. However, the molecular ...mechanism underlying the mechanical signal transduction in osteocytes is not well understood. Here, we found that Yoda1, a selective Piezo1 agonist, increased intracellular calcium mobilization and dose-dependently decreased the expression of Sost (encoding Sclerostin) in the osteocytic cell line IDG-SW3. We also demonstrated that mechanical stretch of IDG-SW3 suppressed Sost expression, a result which was abrogated by treatment with the Piezo1 inhibitor GsMTx4, and the deficiency of Piezo1. Furthermore, the suppression of Sost expression was abolished by treatment with an Akt inhibitor. Taken together, these results indicate that the activation of the Piezo1-Akt pathway in osteocytes is required for mechanical stretch-induced downregulation of Sost expression.
•Osteocytic IDG-SW3 cells express functional Piezo1.•A Piezo1 agonist Yoda1 suppresses Sost expression in osteocytic IDG-SW3 cells.•Mechanically stretched osteocytic IDG-SW3 cells exhibit decreased Sost expression.•Sost suppression is completely abrogated by the deficiency of Piezo1.•Mechanical stretch induces Sost suppression via Piezo1-Akt pathway in osteocytes.
Triangle mechanisms for
B
0
→
(
J
/
ψ
π
+
π
-
)
K
+
π
-
are studied. Experimentally, an
X
(3872) peak has been observed in this process. When the final
(
J
/
ψ
π
+
π
-
)
π
invariant mass is around ...the
D
∗
D
¯
∗
threshold, one of the triangle mechanisms causes a triangle singularity and generates a sharp
X
(3872)-like peak in the
J
/
ψ
π
+
π
-
invariant mass distribution. The Breit–Wigner mass and width fitted to the spectrum are 3871.68 MeV (a few keV above the
D
∗
0
D
¯
0
threshold) and
∼
0.4 MeV, respectively. These Breit-Wigner parameters hardly depend on a choice of the model parameters. Comparing with the precisely measured
X
(3872) mass and width,
3871.69
±
0.17
MeV and
<
1.2
MeV, the agreement is remarkable. When studying the
X
(3872) signal from this process, this non-resonant contribution has to be understood in advance. We also study a charge analogous process
B
0
→
(
J
/
ψ
π
0
π
-
)
K
+
π
0
. A similar triangle singularity exists and generates an
X
-
(
3876
)
-like peak.
The (
e
,
e′K
+
) reaction spectroscopy opened a door to high resolution spectroscopy of Λ hypernuclei at JLab and it is currently the only technique to give sub-MeV energy resolution for reaction ...spectroscopy of wide-mass range Λ hypernuclei. New experiments from light to heavy hypernuclei are under preparation at JLab to solve hypertriton puzzle, to clarify charge symmetry breaking of Λ hypernuclei and to give a clue to solve the hyperon puzzle or the puzzle of heavy neutron stars.
As a hypernuclear precision spectroscopy experiment with other than electron beams, there is a newly proposed experiment using the (
π
+
,
K
+
) reaction at the new HIHR beamline, which is a key facility in the J-PARC hadron experimental facility extension project. The HIHR beamline adopts the momentum dispersion match technique and will enable us to perform sub-MeV resolution spectroscopy for isospin partners to the Λ hypernuclei studied with the electron beams at JLab.
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