q*d
发帖数: 22178 | 1 吗?
http://news.xinhuanet.com/english/world/2013-04/03/c_132283285.
AMS announces first results in search for dark matter
English.news.cn 2013-04-03 23:22:14
Samuel Ting, Chinese-American principal scientist for the Alpha Magnetic
Spectrometer (AMS) project, is interviewed at the European Organisation for
Nuclear Research's (CERN) near Geneva, April 3, 2013. The AMS team led by
Nobel laureate Samuel Ting announced on Wednesday the first results in the
search for dark matter, reporting an excess of positrons in the cosmic ray
flux. (Xinhua/Wang Siwei)
GENEVA, April 3 (Xinhua) -- The Alpha Magnetic Spectrometer (AMS) team led
by Nobel laureate Samuel Ting announced on Wednesday the first results in
the search for dark matter, reporting an excess of positrons in the cosmic
ray flux.
Ting's team found out that the positron fraction increases from 10 GeV to
250 GeV, with the data showing the slope of the increase reducing by an
order of magnitude over the range 20-250 GeV. The data also show no
significant variation over time, or any preferred incoming direction.
These results are consistent with the positrons originating from the
annihilation of dark matter particles in space, but not yet sufficiently
conclusive to rule out other explanations.
"Over the coming months, AMS will be able to tell us conclusively whether
these positrons are a signal for dark matter, or whether they have some
other origin," said AMS spokesperson Ting.
The AMS results, to be published in the journal Physical Review Letters,
were based on some 25 billion recorded events, including 400,000 positrons
with energies between 0.5 GeV and 350 GeV, recorded over 18 months,
according to Ting.
This represented the largest collection of antimatter particles recorded in
space.
Cosmic rays are charged high-energy particles that permeate space. The AMS
experiment, installed on the International Space Station, is designed to
study them before they have a chance to interact with the Earth's atmosphere.
An excess of antimatter within the cosmic ray flux was first observed around
two decades ago. One possibility for the origin of the excess, predicted by
a theory known as supersymmetry, is that positrons could be produced when
two particles of dark matter collide and annihilate.
However, the AMS measurement cannot yet rule out the alternative explanation
that the positrons originate from pulsars distributed around the galactic
plane. Supersymmetry theories also predict a cut-off at higher energies
above the mass range of dark matter particles, and this has not yet been
observed.
"AMS is the first experiment to measure to one percent accuracy in space. It
is this level of precision that will allow us to tell whether our current
positron observation has a dark matter or pulsar origin," Ting said.
Dark matter is one of the most important mysteries of physics. Accounting
for over a quarter of the universe's mass-energy balance, it can be observed
indirectly through its interaction with visible matter but has yet to be
directly detected.
Launched on May 16, 2011 by the shuttle Endeavor in its last mission, the
AMS-2 started to send data back to the earth on May 19. The first results
were based on data collected from May 2011 to Dec. 2012, he said. | C********n
发帖数: 6682 | 2 标题党一律押往秦城
for
【在 q*d 的大作中提到】
: 吗?
: http://news.xinhuanet.com/english/world/2013-04/03/c_132283285.
: AMS announces first results in search for dark matter
: English.news.cn 2013-04-03 23:22:14
: Samuel Ting, Chinese-American principal scientist for the Alpha Magnetic
: Spectrometer (AMS) project, is interviewed at the European Organisation for
: Nuclear Research's (CERN) near Geneva, April 3, 2013. The AMS team led by
: Nobel laureate Samuel Ting announced on Wednesday the first results in the
: search for dark matter, reporting an excess of positrons in the cosmic ray
: flux. (Xinhua/Wang Siwei)
| x****u
发帖数: 44466 | 3 老丁就是标题党。这能算发现的话，意大利中微子测速的科学家就死的太冤了。
for
【在 q*d 的大作中提到】
: 吗?
: http://news.xinhuanet.com/english/world/2013-04/03/c_132283285.
: AMS announces first results in search for dark matter
: English.news.cn 2013-04-03 23:22:14
: Samuel Ting, Chinese-American principal scientist for the Alpha Magnetic
: Spectrometer (AMS) project, is interviewed at the European Organisation for
: Nuclear Research's (CERN) near Geneva, April 3, 2013. The AMS team led by
: Nobel laureate Samuel Ting announced on Wednesday the first results in the
: search for dark matter, reporting an excess of positrons in the cosmic ray
: flux. (Xinhua/Wang Siwei)
| q*d
发帖数: 22178 | 4 丁的credit比意大利人强多了吧,
这次丁是六个组独立分析数据,结果一致后发表.
丁要有意大利人的勇气,J/ψ根本轮不到SLAC也出一个炸药奖.
by
the
ray
【在 x****u 的大作中提到】
: 老丁就是标题党。这能算发现的话，意大利中微子测速的科学家就死的太冤了。
:
: for
| x****u
发帖数: 44466 | 5 扯淡没有这么扯的，意大利要是把实验放在空间站上做，你也找不出插头哪里松了。
物理学家改行研究宗教的都有，这点credit算不了什么。
【在 q*d 的大作中提到】
: 丁的credit比意大利人强多了吧,
: 这次丁是六个组独立分析数据,结果一致后发表.
: 丁要有意大利人的勇气,J/ψ根本轮不到SLAC也出一个炸药奖.
:
: by
: the
: ray
| s***n
发帖数: 678 | 6 比上次AMS的结果promising了。估计可以开始忽悠下一步投资，拿到让仪器在天上转20
年的启动经费。话说今天看杂志才知道国际空间站花了这么多钱，号称要为全人类谋福
利，上面真正意义的科研仪器只有AMS一个。就为了国际空间站的遮羞布，AMS也该在上
面站岗。
for
【在 q*d 的大作中提到】
: 吗?
: http://news.xinhuanet.com/english/world/2013-04/03/c_132283285.
: AMS announces first results in search for dark matter
: English.news.cn 2013-04-03 23:22:14
: Samuel Ting, Chinese-American principal scientist for the Alpha Magnetic
: Spectrometer (AMS) project, is interviewed at the European Organisation for
: Nuclear Research's (CERN) near Geneva, April 3, 2013. The AMS team led by
: Nobel laureate Samuel Ting announced on Wednesday the first results in the
: search for dark matter, reporting an excess of positrons in the cosmic ray
: flux. (Xinhua/Wang Siwei)
| x****u
发帖数: 44466 | 7 ISS的主要科学目的是动物实验，具体说就是研究人类抗辐射能力。
20
【在 s***n 的大作中提到】
: 比上次AMS的结果promising了。估计可以开始忽悠下一步投资，拿到让仪器在天上转20
: 年的启动经费。话说今天看杂志才知道国际空间站花了这么多钱，号称要为全人类谋福
: 利，上面真正意义的科研仪器只有AMS一个。就为了国际空间站的遮羞布，AMS也该在上
: 面站岗。
:
: for
|
|
