Clearing the bar

Physics World ◽  
2021 ◽  
Vol 34 (11) ◽  
pp. 28v-28v
Author(s):  
Chris Atkins
Keyword(s):  

A clarification on the letter “The missing mass”, concerning the pole vault in question 8 of the decathlon puzzle “Sporting chance”.

1998 ◽  
Vol 116 (2) ◽  
pp. 782-788 ◽  
Author(s):  
Olin J. Eggen
Keyword(s):  
The Sun ◽  

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Yudai Ichikawa ◽  
Junko Yamagata-Sekihara ◽  
Jung Keun Ahn ◽  
Yuya Akazawa ◽  
Kanae Aoki ◽  
...  

Abstract We have measured, for the first time, the inclusive missing-mass spectrum of the $^{12}$C$(K^-, p)$ reaction at an incident kaon momentum of 1.8 GeV/$c$ at the J-PARC K1.8 beamline. We observed a prominent quasi-elastic peak ($K^-p \rightarrow K^-p$) in this spectrum. In the quasi-elastic peak region, the effect of secondary interaction is apparently observed as a peak shift, and the peak exhibits a tail in the bound region. We compared the spectrum with a theoretical calculation based on the Green’s function method by assuming different values of the parameters for the $\bar{K}$–nucleus optical potential. We found that the spectrum shape in the binding-energy region $-300 \, \text{MeV} < B_{K} < 40$ MeV is best reproduced with the potential depths $V_0 = -80$ MeV (real part) and $W_0 = -40$ MeV (imaginary part). On the other hand, we observed a significant event excess in the deeply bound region around $B_{K} \sim 100$ MeV, where the major decay channel of $K^- NN \to \pi\Sigma N$ is energetically closed, and the non-mesonic decay modes ($K^- NN \to \Lambda N$ and $\Sigma N$) should mainly contribute. The enhancement is fitted well by a Breit–Wigner function with a kaon-binding energy of 90 MeV and width 100 MeV. A possible interpretation is a deeply bound state of a $Y^{*}$-nucleus system.


2021 ◽  
Vol 9 (1) ◽  
pp. 232596712097339
Author(s):  
Shota Enoki ◽  
Mami Nagao ◽  
Soju Ishimatsu ◽  
Takuya Shimizu ◽  
Rieko Kuramochi

Background: Athletes participating in track and field jumping events (long jump, triple jump, high jump, and pole vault) are exposed to ground-reaction forces on the takeoff leg that are several times their body weight. This can cause injuries specific to such activities. Purpose: To determine the incidence of injuries in collegiate jumpers using the guidelines set forth by a 2014 consensus statement on injury surveillance during track and field events. Study Design: Descriptive epidemiology study. Methods: A total of 51 jumpers between April 2016 and March 2017 and 54 jumpers between April 2017 and March 2018 participated in this study. All athletes were from a single college in Japan. Baseline information on athletes participating in the long jump, triple jump, high jump, and pole vault was collected at study enrollment. Practice and competition exposures were reported by the team trainer. Injury incidence was calculated as the number of injuries per 1000 athlete-exposures (AEs). Results: A total of 147 injuries were reported among 16,998 exposures (8.65 injuries per 1000 AEs). The most common injury locations were the posterior thigh and lateral ankle (17.0%), followed by the posterior foot or toe (12.9%); the most frequent type of injury was strain/muscle rupture/tear (21.1%). The most common injury for long jumpers was ankle sprain (23.3%); for high jumpers, flexor hallucis longus tendinosis (15.8%); and for pole vaulters, hamstring strain (13.2%). Conclusion: The overall characteristics are different for each event; therefore, injuries for each event need to be investigated.


Entropy ◽  
2017 ◽  
Vol 19 (7) ◽  
pp. 315
Author(s):  
Daniel Berend ◽  
Aryeh Kontorovich ◽  
Gil Zagdanski
Keyword(s):  

2013 ◽  
Vol 128 (2) ◽  
pp. 669-723 ◽  
Author(s):  
Henrik J. Kleven ◽  
Mazhar Waseem

Abstract We develop a framework for nonparametrically identifying optimization frictions and structural elasticities using notches—discontinuities in the choice sets of agents—introduced by tax and transfer policies. Notches create excess bunching on the low-tax side and missing mass on the high-tax side of a cutoff, and they are often associated with a region of strictly dominated choice that would have zero mass in a frictionless world. By combining excess bunching (observed response attenuated by frictions) with missing mass in the dominated region (frictions), it is possible to uncover the structural elasticity that would govern behavior in the absence of frictions and arguably capture long-run behavior. We apply our framework to tax notches in Pakistan using rich administrative data. While observed bunching is large and sharp, optimization frictions are also very large as the majority of taxpayers in dominated ranges are unresponsive to tax incentives. The combination of large observed bunching and large frictions implies that the frictionless behavioral response to notches is extremely large, but the underlying structural elasticity driving this response is nevertheless modest. This highlights the inefficiency of notches: by creating extremely strong price distortions, they induce large behavioral responses even when structural elasticities are small.


2001 ◽  
Vol 69 (1) ◽  
pp. 93-94
Author(s):  
Lawrence Krauss ◽  
Virginia Trimble
Keyword(s):  

Physics World ◽  
2021 ◽  
Vol 34 (10) ◽  
pp. 25v-25v
Author(s):  
Chris Atkins

In response to the Lateral Thoughts quiz “Sporting chance”, in which question 8 asked for a rough estimate of the theoretical maximum height a pole vaulter could jump, and why the actual world record is slightly above this.


2004 ◽  
Vol 13 (10) ◽  
pp. 2275-2279 ◽  
Author(s):  
J. A. R. CEMBRANOS ◽  
A. DOBADO ◽  
A. L. MAROTO

Extra-dimensional theories contain additional degrees of freedom related to the geometry of the extra space which can be interpreted as new particles. Such theories allow to reformulate most of the fundamental problems of physics from a completely different point of view. In this essay, we concentrate on the brane fluctuations which are present in brane-worlds, and how such oscillations of the own space–time geometry along curved extra dimensions can help to resolve the Universe missing mass problem. The energy scales involved in these models are low compared to the Planck scale, and this means that some of the brane fluctuations distinctive signals could be detected in future colliders and in direct or indirect dark matter searches.


1971 ◽  
Vol 30 (3) ◽  
pp. 323-329 ◽  
Author(s):  
W. Yourgrau ◽  
J. F. Woodward
Keyword(s):  

2004 ◽  
Vol 18 (04n05) ◽  
pp. 519-525 ◽  
Author(s):  
FRANCESCO CALOGERO

An estimate is presented of the angular momentum associated with the stochastic cosmic tremor, which has been hypothesized to be caused by universal gravitation and by the granularity of matter, and to be itself the cause of quantization ("cosmic origin of quantization"). If that universal tremor has the spatial coherence which is instrumental in order that the estimated action associated with it have the order of magnitude of Planck's constant h, then the estimated order of magnitude of the angular momentum associated with it also has the same value. We moreover indicate how these findings (originally based on a simplified model of the Universe, as being made up only of particles having the nucleon mass) are affected (in fact, essentially unaffected) by the possible presence in the mass of the Universe of a large component made up of particles much lighter than nucleons ("dark", or "missing", mass).


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