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1.
The mass neutrino interference phase in a global monopole space time along the null trajectory and the geodesic is studied,
and we find that the conserved energy changes a factor when a particle travels along the geodesic, if compared with the energy
in the space time without the global monopole. The oscillation phase is increased by a factor due to the correction of the
global monopole, comparing with the case in Schwarzschild space time. We obtain that the type-I phase along both the null
and geodesic has a difference of a factor of 1−8π
η
2, and that the phase along the geodesic is the double of that along the null. 相似文献
2.
Yu. A. Simonov 《JETP Letters》2008,87(3):121-123
The dipion spectrum for the ϒ(nS) → ϒ(n′S) transition with n < 4 has the form dw/dq ∼ (phase space) |η − x|2, with x = q
2 − 4m
π2 / (ΔM)2 − 4m
π2 < q
2 ≡ M
ππ2, and ΔM = M(nS) − M(n′S). The parameter η is calculated and the spectrum is shown to reproduce the experimental data for all three types of decays:
3 → 1, 2 → 1, and 3 → 2 with η ≈ 0.5, 0, and −3, respectively.
The text was submitted by the author in English. 相似文献
3.
For I
G
(J
PC)=1−(1−+) exotic waves in the reactions ρπ → ρπ, ρπ → ηπ, ρπ → η′π, and ρπ →
and in allied reactions, a model is constructed that satisfies the conditions of unitarity and analyticity and which employs,
as an input, an “anomalous” nondiagonal VPPP interaction relating the ρπ, ηπ, η′π, and
channels. The possibility of obtaining, within this simple field-theoretical model, a resonance behavior of the I
G(J
PC)=1−(1−+) amplitudes corresponding to the {10} −
and {8} representations of the SU(3) group and their mixing is demonstrated explicitly in the mass range 1.3–1.6 GeV, where data of present-day experiments
suggest a rich exoticism.
__________
Translated from Yadernaya Fizika, Vol. 65, No. 3, 2002, pp. 579–588.
Original Russian Text Copyright ? 2002 by Achasov, Shestakov. 相似文献
4.
In this paper, we research the dynamical evolution and quasinormal modes of nonminimal derivative coupling scalar field in
Reissner-Nordstr?m spacetime with a global monopole. We also find that Hawking radiation behavior near the event horizon is
similar to the scalar field case. In the whole spacetime, the conclusions show that weak coupling field will affect the dynamical
behavior delicately, but the strong coupling constant η results in the deformation of dynamical evolution curve. When η > η
c
, the black hole system will not be stable. The break from the global monopole also intensely affect the dynamical behavior
of this black hole spacetime. Furthermore, the break will promote the instability of the coupling field. 相似文献
5.
In this article, we study the decays ψ′ → J/ψπ
+
π
− and η′c → η
c
π
+
π
− by taking into account the chiral symmetry breaking effects, the final-state interactions and the heavy-quark symmetry. We
can confront the predictions of the η′c → η
c
π
+
π
− decay width and differential decay width with the experimental data in the future, and obtain powerful constraints on the
chiral breaking effects and the final-state interactions, and test the heavy-quark symmetry. 相似文献
6.
V. Bernard N. Kaiser Ulf-G. Meißner 《The European Physical Journal A - Hadrons and Nuclei》1999,4(3):259-275
We evaluate the threshold matrix–element for the reaction pp→ppπ0 in a fully relativistic Feynman diagrammatic approach. We employ a simple effective range approximation to take care of the
S–wave pp final–state interaction. The experimental value for the threshold amplitude A = (2.7 −i0.3) fm4 can be reproduced by contributions from tree level chiral (long–range) pion exchange and short–range effects related to vector
meson exchanges, with ω-exchange giving the largest individual contribution. Pion loop effects appear to be small. We stress
that the commonly used heavy baryon formalism is not applicable in the NN–system above the pion production threshold due to
the large external momentum, |p|≃ (Mm
π)−1/2, with M and m
π the nucleon and the pion mass, respectively. We furthermore investigate the reaction pp→pnπ+ near threshold within the same approach. We extract from the data the triplet threshold amplitude as B = (2.8 −i1.5) fm4. Its real part can be well understood from (relativistic) tree level meson–exchange diagrams. In addition, we investigate
the process pp→ppη near threshold. We use a simple factorization ansatz for the ppη final–state interaction and extract from the data the modulus of the threshold amplitude, |C|= 1.32 fm4. With g
ηN= 5.3, this value can be reproduced by (relativistic) tree level meson–exchange diagrams and η–rescattering, whose strength
is fixed by the ηN scattering length. We also comment on the recent near threshold data for η′–production.
Received: 27 November 1998 相似文献
7.
Bastian Kubis Sebastian P. Schneider 《The European Physical Journal C - Particles and Fields》2009,62(3):511-523
Strong final-state interactions create a pronounced cusp in η′→η
π
0
π
0 decays. We adapt and generalize the non-relativistic effective field theory framework developed for the extraction of π
π scattering lengths from K→3π decays to this case. The cusp effect is predicted to have an effect of more than 8% on the decay spectrum below the π
+
π
− threshold. 相似文献
8.
Christoph?Ditsche Bastian?Kubis Ulf-G.?Mei?ner 《The European Physical Journal C - Particles and Fields》2009,60(1):83-105
We re-evaluate the electromagnetic corrections to η→3π decays at next-to-leading order in the chiral expansion, arguing that effects of order e
2(m
u
−m
d
) disregarded so far are not negligible compared to other contributions of order e
2 times a light-quark mass. Despite the appearance of the Coulomb pole in η→π
+
π
−
π
0 and cusps in η→3π
0, the overall corrections remain small. 相似文献
9.
From the Copson and Linet solution for the electrostatic field due to a point charge near a Schwarzschild black hole, we have
deduced the field due to two equal charges placed symmetrically (diametrically opposite) about the hole. It turns out that
the motion of a test-charged particle is completely solvable only in the equatorial plane, because theϑ-equation does not yield the first integral forϑ ≠π/2. We have however considered circular orbits about the axis forϑ=constant ≠π/2 by requiring bothϑ andr to remain fixed all through the motion. Forϑ ≠π/2 orbits, in contrast to the similar classical situation, there occur forbiddenϑ-ranges. This seems to be a relativistic effect. 相似文献
10.
We study the stability and the properties of the ground state of neutral systems containing up to four positively charged
bosons and their antiparticles. Examples are the di-pionium molecule (π
+
π
−)2, which is almost identical to the positronium molecule (e
+
e
−)2, the tri-pionium (π
+
π
−)3, and the quadri-pionium (π
+
π
−)4 molecules. We briefly compare our results on the energy to those on the large-N limit of (π
+
π
−)
N
. We also show that the annihilation probability can be calculated accurately with simple wave functions when one uses the
generalized Schwinger rule.
Received September 5, 1994; accepted for publication October 15, 1994 相似文献
11.
The decays η → 3π
0 and η → π
0
π
+
π
− are considered within the isobar model. It is shown that, in order to explain the branching ratio and the shape of the Dalitz
plot for the decay η′ → 3π
0, it is sufficient to take into account the contributions of the σ and a
0 mesons. The inclusion of the σ meson is necessary for reproducing the shape of the distribution over the Dalitz plot. The branching ratio for the decay
η′ → π
0
π
+
π
− is obtained. The predictions for the distributions over the Dalitz plot for this decay are presented. These predictions depend
strongly on model parameters. 相似文献
12.
Hatem Zaag 《Communications in Mathematical Physics》2002,225(3):523-549
We consider u(x,t) a solution of u
t
=Δu+|u|
p
− 1
u that blows up at time T, where u:ℝ
N
×[0, T)→ℝ, p>1, (N−2)p<N+2 and either u(0)≥ 0 or (3N−4)p<3N+8. We are concerned with the behavior of the solution near a non isolated blow-up point, as T−t→ 0. Under a non-degeneracy condition and assuming that the blow-up set is locally continuous and N−1 dimensional, we escape logarithmic scales of the variable T−t and give a sharper expansion of the solution with the much smaller error term (T−t)1, 1/2−η for any η>0. In particular, if in addition p>3, then the solution is very close to a superposition of one dimensional solutions as functions of the distance to the blow-up
set. Finally, we prove that the mere hypothesis that the blow-up set is continuous implies that it is C
1, 1/2−η for any η>0.
Received: 20 June 2001 / Accepted: 6 October 2001 相似文献
13.
A. Starostin 《The European physical journal. Special topics》2011,198(1):117-131
Decays of the η and the η′ represent a significant portion of the scientific program with the Crystal Ball at MAMI. This review
summarizes the current status of the program and discusses some recent results, such as the slope parameter of the η → 3π0 Dalitz plot, the matrix element of η → π0γγ and the invariant mass of e
+
e
−γ from the η → e
+
e
−γ Dalitz decay. Possible future measurements are discussed. 相似文献
14.
Recently [see V.V. Anisovich et al., Yad. Fiz. 63, 1489 (2000)], the K-matrix solutions for the wave IJ
PC=00++ were obtained in the mass region 450–1900 MeV, where four resonances f
0(980), f
0(1300), f
0(1500), f
0(1750) and the broad state f
0(1530
−250
+90
) are located. Based on these solutions, partial widths are determined for scalar-isoscalar states decaying into the channels
ππ, KK
ηη, ηη′, ππππ and corresponding decay couplings.
From Yadernaya Fizika, Vol. 65, No. 8, 2002, pp. 1583–1590.
Original English Text Copyright ? 2002 by Anisovich, Nikonov, Sarantsev.
This article was submitted by the authors in English. 相似文献
15.
V. Dorofeev R. Dzhelyadin A. Ekimov Yu. Gavrilov Yu. Gouz A. Ivashin V. Kabachenko I. Kachaev A. Karyukhin Yu. Khokhlov V. Konstantinov M. Makouski V. Matveev A. Myagkov V. Nikolaenko A. Ostankov B. Polyakov D. Ryabchikov N. Shalanda M. Soldatov A. A. Solodkov A. V. Solodkov O. Solovianov E. Starchenko A. Zaitsev 《The European Physical Journal A - Hadrons and Nuclei》2008,38(2):149-154
The isospin-violating decay f
1(1285) → π+π-π0 has been studied at the VES facility. This study is based on the statistics acquired in π-
Be interactions at 27, 36.6 and 41 GeV/c in the diffractive reaction π-
N → (f
1π-)N . The f
1(1285) → π+π-π0 decay is observed. The preliminary ratio of decay probabilities BR(f
1(1285) → π+π-π0) to BR(f
1(1285) → ηπ+π-).
BR(η → γγ) is ∼ 2% .
Original article based on material presented at HADRON 2007. 相似文献
16.
T. Datta 《Il Nuovo Cimento D》1983,2(3):783-786
Summary The fission of a vortex line along the trajectory of a monopole in a superconducting medium is an unambiguous signature of
a monopole. The numbern of the (stable) daughter vortices determines the monopole strengthg withg=2nφ/4π where ϕ0=2.07·10−7 G cm2.
Riassunto La fissione di una linea di vortice lungo la traiettoria di un monopolo in un mezzo superconduttore è indice sicuro della segnatura di un monopolo. Il numeron di vortici figli (stabili) determina la forza del monopolog cong=nϕ0/4π, dove ϕ0=2.07·10−7 G cm2.相似文献
17.
High-statistics data on the γγ → π0η reaction will make it possible to conclude whether the K
+
K
−-loop rescattering mechanism, γγ → K
+
K
− → a
0(980) → π0η, is the main mechanism of the production of a
0(980) isovector resonance. This mechanism provides a reasonable value of 20–30 nb at the maximum for the manifestation of
a
0(980) in the γγ → π0η cross section. It also gives rise to a noticeable narrowing of the a
0(980) peak to its effective (observed) width ≈20–30 MeV in the γγ → π0η channel. The decay width averaged over the resonance mass distribution is 〈Γα
0 → K
+
K
− → γγ〉πη ≈ 0.13 keV. The experimental confirmation of this scenario would be important evidence in favor of the q
2
$
\bar q
$
\bar q
2 nature of light scalar mesons. 相似文献
18.
V. M. Aul’chenko M. N. Achasov A. V. Bozhenok A. D. Bukin D. A. Bukin S. V. Burdin I. A. Gaponenko V. B. Golubev T. V. Dimova S. I. Dolinskii V. P. Druzhinin M. S. Dubrovin V. N. Ivanchenko P. M. Ivanov A. A. Korol’ S. V. Koshuba A. A. Mamutkin E. V. Pakhtusova S. I. Serednyakov V. A. Sidorov Z. K. Silagadze Yu. V. Usov V. V. Sharyi Yu. M. Shatunov 《JETP Letters》1999,69(2):97-102
A search for the process e
+
e
−→φ(1020)→η″(958) γ in the decay channel η″→π
+
π
−
η, η→γγ was made in an experiment at the VEPP-2M e
+
e
− collider with the SND detector. Analysis confirms the occurrence of φ→η″γ decay with probability B(φ→η″ γ)=(6.7
−2.9
+3.4
)×10−5.
Pis’ma Zh. éksp. Teor. Fiz. 69, No. 2, 87–91 (25 January 1999) 相似文献
19.
Yu. A. Simonov 《Physics of Atomic Nuclei》2008,71(6):1048-1076
The mechanism of dipion transitions nS → n′Sππ (n = 3, 2; n′ = 2, 1) in bottomonium and charmonium is studied with the use of the chiral string-breaking Lagrangian allowing for the
emission of any number of π(K, ν), and not containing fitting parameters. The transition amplitude contains two terms: M = a − b, where the first term (a) refers to subsequent one-pion emission, , and the second term (b) refers to two-pion emission, . The one parameter formula for the dipion mass distribution is derived, dw/dq∼ (phase space) × | η − x|2, where x = (q
2 − 4m
π2)/(q
max2 − 4m
π2), q
2 m= M
ππ2. The parameter ν dependent on the process is calculated, using SHO wave functions and imposing PCAC restrictions (Adler zero) on amplitudes
a and b. The resulting dipion mass distributions are in agreement with experimental data.
The text was submitted by the authors in English. 相似文献
20.
G. Fabritius G. Flik J. Golczewski D. Herlach G. Jünemann M. Krenke K. Maier A. P. Pathak H. Rempp A. Seeger W. Sigle E. Widmann D. W. Cooke 《Hyperfine Interactions》1986,31(1-4):229-234
By means of π+/μ+ channelling, positive pions (π+) implanted intoTa, Mo, andW are investigated up to high temperatures. A striking observation is that the channelling effect disappears in a rather narrow
temperature interval centred at 0.26 (Ta) to 0.51 (W) of the melting temperature. From studies of π+ trapping by oxygen atoms inTa estimates for the low-temperature π+ diffusivity inTa [D
π(23K)=1.4·10−10±0.3 m2s−1,D
π(47K)=5.7·10−10±0.3 m2s−1] as well as for the binding enthalpy of π+ to 0 atoms (H
B=7·10−2 eV) have been obtained. The diffusion data are in reasonable agreement with the theory of phonon-assisted tunnelling. 相似文献