共查询到20条相似文献,搜索用时 31 毫秒
1.
Saebyok Bae Byungchul Chung P. Ko 《The European Physical Journal C - Particles and Fields》2008,54(4):601-616
The CP violating phases in soft SUSY breaking terms may induce indirect CP violation in the neutral Higgs boson sector through
SUSY particle loops as well as direct CP violation in the γγ→Hi (i=1,2,3) through CP violating vertices. We present a complete analysis of the MSSM Higgs sector CP violation at photon colliders
including the chargino loop contributions in the regime , where the CP violating mixing in the neutral Higgs sector is very strongly influenced by the scalar top loop, more so than
the chargino and neutralino ones. However, the CP violating phases of the higgsino and wino mass parameters may still generate
direct CP violation in γγ→Hi. In this process, the CP violating phenomena become very rich, and thus we study the production rates and polarization asymmetries
in the Higgs production in detail. Photon colliders with high luminosity and well controlled polarized initial photon beams
are indispensable in determining the CP properties of neutral Higgs bosons.
PACS 14.80.Cp; 12.60.Jv; 11.30.Er 相似文献
2.
A. Bartl H. Fraas S. Hesselbach K. Hohenwarter-Sodek T. Kernreiter G. Moortgat-Pick 《The European Physical Journal C - Particles and Fields》2007,51(1):149-161
We study CP violation in chargino production and decay in the minimal supersymmetric standard model (MSSM) with complex parameters
at an e+e- linear collider with longitudinally polarised beams. We investigate CP-sensitive asymmetries by means of triple product correlations
and study their dependence on the complex parameters M1 and μ. We give numerical predictions for the asymmetries and their measurability at the future International Linear Collider.
Our results show that the CP asymmetries can be measured in a large region of the MSSM parameter space. 相似文献
3.
We discuss the use of fermion polarization for studying neutral Higgs bosons at a photon collider. To this aim we construct
polarization asymmetries which can isolate the contribution of a Higgs boson ϕ in γγ → f
, f = τ/t, from that of the QED continuum. This can help in getting information on the γγϕ coupling in case ϕ is a CP eigenstate. We also construct CP-violating asymmetries which can probe CP mixing in case ϕ has indeterminate CP. Furthermore, we take the MSSM with CP violation as an example to demonstrate the potential of these
asymmetries in a numerical analysis. We find that these asymmetries are sensitive to the presence of a Higgs boson as well
as its CP properties over a wide range of MSSM parameters.
相似文献
4.
In the NMSSM, because of introducing a complex singlet superfield, the lightest CP-odd Higgs boson, a
1, can be a singlet-like state with a tiny doublet component in large regions of parameter space. In this paper, we examine
the discovery potential of a
1 produced in association with a bottom–antibottom pair at the LHC through τ
+
τ
− and γγ decay modes. It is shown that an a
1 with mass ≤M
Z
can be extracted from the SM backgrounds by using the τ
+
τ
− decay channel, a possibility precluded to the MSSM. In contrast, the γγ decay mode is overwhelmed by backgrounds despite the fact that the branching ratio of this mode can reach unity when a
1 is a pure singlet. 相似文献
5.
S.Y. Choi B.C. Chung J. Kalinowski Y.G. Kim K. Rolbiecki 《The European Physical Journal C - Particles and Fields》2006,46(2):511-520
Neutralinos
in supersymmetric theories, the spin–1/2 Majorana–type superpartners of the U(1) and SU(2) neutral electroweak gauge bosons
and SU(2) neutral Higgs bosons, are expected to be among light supersymmetric particles so that they can be produced copiously
via direct pair production and/or from cascade decays of other sparticles such as sleptons at the planned Large Hadron Collider
and the prospective International Linear Collider. Considering the prospects of having both highly polarized neutralinos and
possibility of reconstructing their decay rest frames, we provide a systematic investigation of the three–body leptonic decays
of the neutralinos in the minimal supersymmetric standard model and demonstrate alternative ways for probing the Majorana
nature of the neutralinos and CP violation in the neutralino system. 相似文献
6.
M. Carena S. Heinemeyer C. E. M. Wagner G. Weiglein 《The European Physical Journal C - Particles and Fields》2006,45(3):797-814
The Higgs boson search has shifted from LEP2 to the Tevatron and will subsequently move to the LHC. The current limits from
the Tevatron and the prospective sensitivities at the LHC are often interpreted in specific MSSM scenarios. For heavy Higgs
boson production and subsequent decay into
or τ+τ–, the present Tevatron data allow one to set limits in the MA–tan β plane for small MA and large tan β values. Similar channels have been explored for the LHC, where the discovery reach extends to higher values
of MA and smaller tan β. Searches for MSSM charged Higgs bosons, produced in top decays or in association with top quarks, have
also been investigated at the Tevatron and the LHC. We analyze the current Tevatron limits and prospective LHC sensitivities.
We discuss how robust they are with respect to variations of the other MSSM parameters and possible improvements of the theoretical
predictions for Higgs boson production and decay. It is shown that the inclusion of supersymmetric radiative corrections to
the production cross sections and decay widths leads to important modifications of the present limits on the MSSM parameter
space. The impact on the region where only the lightest MSSM Higgs boson can be detected at the LHC is also analyzed. We propose
to extend the existing benchmark scenarios by including additional values of the higgsino mass parameter μ. This affects only
slightly the search channels for a SM-like Higgs boson, while having a major impact on the searches for non-standard MSSM
Higgs bosons. 相似文献
7.
B. Mawlong 《Pramana》2007,69(4):521-531
The charmless nonleptonic decay modes B → f
0
K(π) involving a scalar and a pseudoscalar meson in the final state are studied. The scalar meson f
0 is considered as a q̄q state, as favored by some recent studies. Using the generalized factorization approach, the branching ratios and CP violation
parameters are computed for these modes. The form factors are calculated using the results from relativistic light front quark
model and the ISGW2 model. It is found that the direct CP violation parameters in these modes are small. However, the obtained
branching ratios are not in agreement with the experimental data. Therefore, these modes may be considered as possible probes
for new physics.
相似文献
8.
E.H. Müller B. Kubis U.-G. Meißner 《The European Physical Journal C - Particles and Fields》2006,48(2):427-440
The charged kaon decay channel K+
ℓ3γ allows for studies of direct CP violation, possibly due to non-standard mechanisms, with the help of T-odd correlation variables. In order to be able to extract a CP-violating signal from experiment, it is necessary to understand all possible standard model phases that also produce T-odd asymmetries. We complement earlier studies by considering strong interaction phases in hadronic structure functions that appear at higher orders in chiral perturbation theory, and we compare our findings to other potential sources of asymmetries. PACS 13.20.Eb; 11.30.Er; 12.39.Fe 相似文献
9.
10.
S. Gennai S. Heinemeyer A. Kalinowski R. Kinnunen S. Lehti A. Nikitenko G. Weiglein 《The European Physical Journal C - Particles and Fields》2007,52(2):383-395
The search for MSSM Higgs bosons will be an important goal at the LHC. We analyze the search reach of the CMS experiment for
the heavy neutral MSSM Higgs bosons with an integrated luminosity of 30 or 60 fb-1. This is done by combining the latest results for the CMS experimental sensitivities based on full simulation studies with
state-of-the-art theoretical predictions of the MSSM Higgs-boson properties. The results are interpreted in MSSM benchmark
scenarios in terms of the parameters tan β and the Higgs-boson mass scale, MA. We study the dependence of the 5σ discovery contours in the MA–tan β plane on variations of the other supersymmetric parameters. The largest effects arise from a change in the higgsino
mass parameter μ, which enters both via higher-order radiative corrections and via the kinematics of Higgs decays into supersymmetric
particles. While the variation of μ can shift the prospective discovery reach (and correspondingly the ”LHC wedge” region)
by about Δtan β=10, we find that the discovery reach is rather stable with respect to the impact of other supersymmetric parameters.
Within the discovery region we analyze the accuracy with which the masses of the heavy neutral Higgs bosons can be determined.
We find that an accuracy of 1–4% should be achievable, which could make it possible in favorable regions of the MSSM parameter
space to experimentally resolve the signals of the two heavy MSSM Higgs bosons at the LHC. 相似文献
11.
Measuring the angle γ of the unitarity triangle is an important part of overconstraining the standard model’s explanation
of CP violation and testing for new physics contributions to CP violation. Although there are many ways to measure γ, all
of them have significant experimental or theoretical challenges. This talk presents progress at the BABAR experiment toward
measuring γ usingB meson decays. 相似文献
12.
Huang Chao-shang 《Frontiers of Physics in China》2007,2(2):212-233
We review the neutral Higgs boson (NHB) contributions to rare leptonic and semi-leptonic B decays in 2HDM and MSSM with large
tan β. We present relevant Wilson coefficients of NHB induced operators. We discuss branching ratios and other observables in those
decays. Finally we present CP violation in rare leptonic B decays.
相似文献
13.
S. Heinemeyer V.A. Khoze M.G. Ryskin W.J. Stirling M. Tasevsky G. Weiglein 《The European Physical Journal C - Particles and Fields》2008,53(2):231-256
We show that the use of forward proton detectors at the LHC installed at 220 m and 420 m distance around ATLAS and/or CMS
can provide important information on the Higgs sector of the MSSM. We analyse central exclusive production of the neutral
-even Higgs bosons h and H and their decays into bottom quarks, τ leptons and W bosons in various MSSM benchmark scenarios.
Using plausible estimates for the achievable experimental efficiencies and the relevant background processes, we find that
the prospective sensitivity of the diffractive Higgs production will allow one to probe interesting regions of the MA–tanβ parameter plane of the MSSM. Central exclusive production of the -even Higgs bosons of the MSSM may provide a unique opportunity to access the bottom Yukawa couplings of the Higgs bosons
up to masses of MH≲ 250 GeV. We also discuss the prospects for identifying the -odd Higgs boson, A, in diffractive processes at the LHC. 相似文献
14.
R. Fleischer S. Recksiegel F. Schwab 《The European Physical Journal C - Particles and Fields》2007,51(1):55-61
Recently, we have seen interesting progress in the exploration of CP violation in B0
d→π+π-: the measurements of mixing-induced CP violation by the BaBar and Belle collaborations are now in good agreement with each
other, whereas the picture of direct CP violation is still unclear. Using the branching ratio and direct CP asymmetry of B0
d→π-K+, this situation can be clarified. We predict , which favours the BaBar result, and we extract γ=(70.0+3.8
-4.3)°, which agrees with the unitarity triangle fits. Extending our analysis to other B→πK modes and B0
s→K+K- with the help of the SU(3) flavour symmetry and plausible dynamical assumptions, we find that all observables with colour-suppressed
electroweak penguin contributions are measured to be in excellent agreement with the standard model. As far as the ratios
Rc,n of the charged and neutral B→πK branching ratios are concerned, which are sizeably affected by electroweak penguin contributions,
our standard-model predictions have almost unchanged central values but significantly reduced errors. Since the new data have
moved quite a bit towards these results, the “B→πK puzzle” for the CP conserving quantities has been significantly reduced.
However, the mixing-induced CP violation of B0
d→π0KS does look puzzling; if confirmed by future measurements, this effect could be accommodated through a modified electroweak
penguin sector with a large CP violating new-physics phase. Finally, we point out that the established difference between
the direct CP asymmetries of B±→π0K± and Bd→π∓K± appears to be generated by hadronic and not by new physics. 相似文献
15.
《The European Physical Journal C - Particles and Fields》2008,56(1):165-170
This paper presents the final interpretation of the results from DELPHI on the searches for Higgs bosons in the minimal supersymmetric
extension of the Standard Model (MSSM). A few representative scenarios are considered, that include CP conservation and explicit
CP violation in the Higgs sector. The experimental results encompass the searches for neutral Higgs bosons at LEP1 and LEP2
in final states as expected in the MSSM, as well as LEP2 searches for charged Higgs bosons and for neutral Higgs bosons decaying
into hadrons independent of the quark flavour. The data reveal no significant excess with respect to background expectations.
The results are translated into excluded regions of the parameter space in the various scenarios. In the CP-conserving case,
these lead to limits on the masses of the lightest scalar and pseudoscalar Higgs bosons, h and A, and on tanβ. The dependence
of these limits on the top quark mass is discussed. Allowing for CP violation reduces the experimental sensitivity to Higgs
bosons. It is shown that this effect depends strongly on the values of the parameters responsible for CP violation in the
Higgs sector. 相似文献
16.
P. Igo-Kemenes 《Pramana》2004,62(3):555-560
During the twelve years of operation of thee
+
e
− collider LEP, the associated collaborations, ALEPH, DELPHI, L3 and OPAL, have extensively searched for Higgs bosons over
a broad range of masses. We present the final results from LEP for the standard model Higgs boson which are obtained from
a statistical combination of the data from the four experiments. We also present preliminary combined results for neutral
Higgs bosons in the minimal supersymmetric model (MSSM) where the Higgs sector is assumed to be CP invariant. Finally, we
discuss an alternative MSSM scenario including CP violation in the Higgs sector. 相似文献
17.
V. V. Skobelev 《Russian Physics Journal》1997,40(2):149-153
The conditions for the formation of an effective photon mass in a strong magnetic field are considered. It is shown that massless
photons are sterile. The channels γ* → e+e− and γ* → vivi for the decay of a massive photon and their possible contribution to the mechanism of energy losses by collapsing astrophysical
objects are discussed.
Moscow State Industrial University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 35–39, February,
1997. 相似文献
18.
V. Remeikis K. Makariūnas A. Dragūnas R. Davidonis R.L. Kalinauskas 《Hyperfine Interactions》2000,128(4):397-408
The γ‐spectrometry method for determination of the relative change ΔλEC/λEC in the partial probability λEC for the 114mIn decay branch by the electron capture (EC), when the nucleus is in different chemical environments, was developed. The method
is based on an experimental determination of the relative change ΔIγ/Iγ in the intensity of the γ‐radiation which is emitted by the excited daughter 114Cd nuclei after EC. The 114mIn decay by EC in indium metal, In2O3 and InAs was compared. The largest ΔIγ/Iγ=(2.5±0.8)·10−4 has been found for InAs relatively to In2O3. The chemical changes in the electron density on the indium nucleus corresponding to the measured ΔIγ/Iγ values have been determined.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
J. Kurpeta A. Andreyev J. Äystö A.-H. Evensen M. Huhta M. Huyse A. Jokinen M. Karny E. Kugler J. Lettry A. Nieminen A. Płochocki M. Ramdhane H.L. Ravn K. Rykaczewski J. Szerypo P. Van Duppen G. Walter A. Wöhr 《The European Physical Journal A - Hadrons and Nuclei》2000,7(1):49-54
The decay of the neutron–rich isotope 216Bi, produced by proton–induced spallation at the PS Booster–ISOLDE facility, was investigated by β-γγ, αγ coincidence and
spectrum-multiscaling measurements. A new method for reducing isobaric contamination enabled to cover the unknown region “east”
of 208Pb for the isobaric chain A=216. The half-life of the β decay of 216Bi was found as T1/2= 135 ± 5 s. Its decay scheme was extended and the possible shell model configurations are proposed.
Received: 13 July 1999 / Revised version: 22 September 1999 相似文献
20.
S. Heinemeyer 《Pramana》2007,69(5):947-951
Electroweak precision measurements can provide indirect information about the possible scale of supersymmetry already at the
present level of accuracy. We review present day sensitivities of precision data in mSUGRA-type models with the gravitino
as the lightest supersymmetric particle (LSP). The χ
2 fit is based on M
W
, sin2
θ
eff, (g−2)
μ
, BR(b → sγ) and the lightest MSSM Higgs boson mass, M
h
. We find indications for relatively light soft supersymmetry-breaking masses, offering good prospects for the LHC and the
ILC, and in some cases also for the Tevatron.
相似文献