Classification of jets with deep learning has gained significant attention in
recent times. However, the performance of deep neural networks is often
achieved at the cost of interpretability. Here we propose an interpretable
network trained on the...
Amit Chakraborty, Motoi Endo, Benjamin Fuks, Björn Herrmann, Mihoko M. Nojiri, Priscilla Pani, Giacomo Polesello
Eur. Phys. J. C78 (2018) 844 2018年8月
We explore signatures related to squark decays in the framework of
non-minimally flavour-violating Supersymmetry. We consider a simplified model
where the lightest squark consists of an admixture of charm and top flavour. By
recasting the existing...
Jets from boosted heavy particles have a typical angular scale which can be
used to distinguish them from QCD jets. We introduce a machine learning
strategy for jet substructure analysis using a spectral function on the angular
scale. The angular ...
Amit Chakraborty, Silvan Kuttimalai, Sung Hak Lim, Mihoko M. Nojiri, Richard Ruiz
Eur. Phys. J. C (2018) 78: 679 2018年5月
In models with colored particle that can decay into a dark
matter candidate , the relevant collider process jets gives rise to events
with significant transverse momentum im...
Keisuke Fujii, Christophe Grojean, Michael E. Peskin, Tim Barklow, Yuanning Gao, Shinya Kanemura, Hyungdo Kim, Jenny List, Mihoko Nojiri, Maxim Perelstein, Roman Pöschl, Jürgen Reuter, Frank Simon, Tomohiko Tanabe, James D. Wells, Jaehoon Yu, Mikael Berggren, Moritz Habermehl, Robert Karl, Gudrid Moortgat-Pick, Sabine Riemann, Junping Tian, Graham W. Wilson, James Brau, Hitoshi Murayama
2018年1月
The International Linear Collider is now proposed with a staged machine
design, with the first stage at ~250 GeV and an integrated
luminosity goal of 2~ab. One of the questions for the machine design is
the importance of positron...
Keisuke Fujii, Christophe Grojean, Michael E. Peskin, Tim Barklow, Yuanning Gao, Shinya Kanemura, Hyungdo Kim, Jenny List, Mihoko Nojiri, Maxim Perelstein, Roman Poeschl, Juergen Reuter, Frank Simon, Tomohiko Tanabe, James D. Wells, Jaehoon Yu, Mikael Berggren, Moritz Habermehl, Sunghoon Jung, Robert Karl, Tomohisa Ogawa, Junping Tian, James Brau, Hitoshi Murayama
2017年10月
The International Linear Collider is now proposed with a staged machine
design, with the first stage at 250 GeV with a luminosity goal of 2 ab-1. In
this paper, we review the physics expectations for this machine. These include
precision measureme...
Keisuke Fujii, Christophe Grojean, Michael E. Peskin, Tim Barklow, Yuanning Gao, Shinya Kanemura, Hyungdo Kim, Jenny List, Mihoko Nojiri, Maxim Perelstein, Roman Pöschl, Jürgen Reuter, Frank Simon, Tomohiko Tanabe, James D. Wells, Jaehoon Yu, Howard Baer, Mikael Berggren, Sven Heinemeyer, Suvi-Leena Lehtinen, Junping Tian, Graham Wilson, Jacqueline Yan, Hitoshi Murayama, James Brau
2017年2月
This paper addresses the question of whether the International Linear
Collider has the capability of discovering new particles that have not already
been discovered at the CERN Large Hadron Collider. We summarize the various
paths to discovery off...
Keisuke Fujii, Christophe Grojean, Michael E. Peskin, Tim Barklow, Yuanning Gao, Shinya Kanemura, Hyungdo Kim, Jenny List, Mihoko Nojiri, Maxim Perelstein, Roman Poeschl, Juergen Reuter, Frank Simon, Tomohiko Tanabe, Jaehoon Yu, James D. Wells, Adam Falkowski, Shigeki Matsumoto, Takeo Moroi, Francois Richard, Junping Tian, Marcel Vos, Hiroshi Yokoya, Hitoshi Murayama, Hitoshi Yamamoto
2016年7月
If the gamma-gamma resonance at 750 GeV suggested by 2015 LHC data turns out
to be a real effect, what are the implications for the physics case and upgrade
path of the International Linear Collider? Whether or not the resonance is
confirmed, this...
Keisuke Fujii, Christophe Grojean, Michael E. Peskin, Tim Barklow, Yuanning Gao, Shinya Kanemura, Hyungdo Kim, Jenny List, Mihoko Nojiri, Maxim Perelstein, Roman Poeschl, Juergen Reuter, Frank Simon, Tomohiko Tanabe, Jaehoon Yu, James D. Wells, Hitoshi Murayama, Hitoshi Yamamoto
2015年6月
We summarize the physics case for the International Linear Collider (ILC). We
review the key motivations for the ILC presented in the literature, updating
the projected measurement uncertainties for the ILC experiments in accord with
the expected ...
Howard Baer, Mikael Berggren, Jenny List, Mihoko M. Nojiri, Maxim Perelstein, Aaron Pierce, Werner Porod, Tomohiko Tanabe
2013年7月
The International Linear Collider (ILC) has recently proven its technical
maturity with the publication of a Technical Design Report, and there is a
strong interest in Japan to host such a machine. We summarize key aspects of
the Beyond the Standa...
Chengcheng Han, Mihoko M. Nojiri, Michihisa Takeuchi, Tsutomu T. Yanagida
2016年9月
Recently ATLAS reported a excess in the stop search with channel. We try to interpret the signal by a light stop
pair production in the MSSM. We find: (1) simple models where stop decays into
a higgsino or a bino...
Biplob Bhattacherjee, Satyanarayan Mukhopadhyay, Mihoko M. Nojiri, Yasuhito Sakaki, Bryan R. Webber
2016年9月
We study the impact of including quark- and gluon-initiated jet
discrimination in the search for strongly interacting supersymmetric particles
at the LHC. Taking the example of gluino pair production, considerable
improvement is observed in the LH...
Chengcheng Han, Koji Ichikawa, Shigeki Matsumoto, Mihoko M. Nojiri, Michihisa Takeuchi
2016年2月
A colored heavy particle with sufficiently small width may form
non-relativistic bound states when they are produced at the large hadron
collider\,(LHC), and they can annihilate into a diphoton final state. The
invariant mass of the diphoton would...
In this paper, we consider phenomenology of a model with an
gauge symmetry. Since the muon couples to the gauge boson
(called boson), its contribution to the muon anomalous magnetic moment
(muon g-2) can account...
Motoi Endo, Takeo Moroi, Mihoko M. Nojiri, Yutaro Shoji
2017年4月
The decay rate of a false vacuum is studied in gauge theory, paying
particular attention to its gauge invariance. Although the decay rate should
not depend on the gauge parameter according to the Nielsen identity, the
gauge invariance of the...
Motoi Endo, Takeo Moroi, Mihoko M. Nojiri, Yutaro Shoji
2017年3月
We study the gauge invariance of the decay rate of the false vacuum for the
model in which the scalar field responsible for the false vacuum decay has
gauge quantum number. In order to calculate the decay rate, one should
integrate out the field f...
Among various models to explain the GeV diphoton resonance hinted at
the LHC Run 2, a class of models where the resonance decays not into a pair of
photons but into a pair of photon-jets is gathering definite attention. In this
paper, we stu...
Daniele Alves, Nima Arkani-Hamed, Sanjay Arora, Yang Bai, Matthew Baumgart, Joshua Berger, Matthew Buckley, Bart Butler, Spencer Chang, Hsin-Chia Cheng, Clifford Cheung, R. Sekhar Chivukula, Won Sang Cho, Randy Cotta, Mariarosaria D'Alfonso, Sonia El Hedri, Rouven Essig, Jared A. Evans, Liam Fitzpatrick, Patrick Fox, Roberto Franceschini, Ayres Freitas, James S. Gainer, Yuri Gershtein, Richard Gray, Thomas Gregoire, Ben Gripaios, Jack Gunion, Tao Han, Andy Haas, Per Hansson, JoAnne Hewett, Dmitry Hits, Jay Hubisz, Eder Izaguirre, Jared Kaplan, Emanuel Katz, Can Kilic, Hyung-Do Kim, Ryuichiro Kitano, Sue Ann Koay, Pyungwon Ko, David Krohn, Eric Kuflik, Ian Lewis, Mariangela Lisanti, Tao Liu, Zhen Liu, Ran Lu, Markus Luty, Patrick Meade, David Morrissey, Stephen Mrenna, Mihoko Nojiri, Takemichi Okui, Sanjay Padhi, Michele Papucci, Michael Park, Myeonghun Park, Maxim Perelstein, Michael Peskin, Daniel Phalen, Keith Rehermann, Vikram Rentala, Tuhin Roy, Joshua T. Ruderman, Veronica Sanz, Martin Schmaltz, Stephen Schnetzer, Philip Schuster, Pedro Schwaller, Matthew D. Schwartz, Ariel Schwartzman, Jing Shao, Jessie Shelton, David Shih, Jing Shu, Daniel Silverstein, Elizabeth Simmons, Sunil Somalwar, Michael Spannowsky, Christian Spethmann, Matthew Strassler, Shufang Su, Tim Tait, Brooks Thomas, Scott Thomas, Natalia Toro, Tomer Volansky, Jay Wacker, Wolfgang Waltenberger, Itay Yavin, Felix Yu, Yue Zhao, Kathryn Zurek
2012 J. Phys. G: Nucl. Part. Phys. 39 105005 2011年5月
This document proposes a collection of simplified models relevant to the
design of new-physics searches at the LHC and the characterization of their
results. Both ATLAS and CMS have already presented some results in terms of
simplified models, and...
Biplob Bhattacherjee, Satyanarayan Mukhopadhyay, Mihoko M. Nojiri, Yasuhito Sakaki, Bryan R. Webber
2015年1月
We show that in studies of light quark- and gluon-initiated jet
discrimination, it is important to include the information on softer
reconstructed jets (associated jets) around a primary hard jet. This is
particularly relevant while adopting a sma...
Present and future expected limits on interactions between dark matter and
various quarks are thoroughly investigated in a model-independent way. In
particular, the constraints on the interactions from the Large Hadron Collider
(LHC) experiment ar...
Perturbative unitarity conditions have been playing an important role by
estimating the energy scale of new physics, including the Higgs mass as one of
the most important examples. In this letter, we show that there is a
possibility to see the hin...
Motoi Endo, Takeo Moroi, Mihoko M. Nojiri, Yutaro Shoji
2015年11月
We study radiative corrections to the decay rate of false vacua, paying
particular attention to the renormalization-scale dependence of the decay rate.
The decay rate exponentially depends on the bounce action. The bounce action
itself is renormal...
Motivated by ATLAS diboson excess around 2 TeV, we investigate a
phenomenology of spin-1 resonances in a model where electroweak sector in the
SM is weakly coupled to strong dynamics. The spin-1 resonances, W' and Z', are
introduced as effective d...
The neutrino minimal Standard Model ({\nu}MSM) is the minimum extension of
the standard model. In this model, the Dodelson-Widrow mechanism (DW) produces
keV sterile neutrino dark matter (DM) and the degenerate GeV heavy Majorana
neutrinos lead to...
Satyanarayan Mukhopadhyay, Mihoko M. Nojiri, Tsutomu T. Yanagida
JHEP10(2014)012 2014年3月
The LHC search for nearly degenerate gluinos and neutralinos, which can
occur, for example, in SUSY axion models, is limited by the reduced missing
transverse momentum and effective mass in the events. We propose the use of
kinematic correlations ...
Masato Yamanaka, Kazunori Kohri, Kunihito Ioka, Mihoko M. Nojiri
Phys. Rev. D. 91 no. 6, 063532 (2015) 2013年10月
We apply the axion-photon conversion mechanism to the 130 GeV -ray
line observed by the Fermi satellite. Near the Galactic center, some
astrophysical sources and/or particle dark matter can produce energetic axions
(or axionlike particles)...
Biplob Bhattacherjee, Shigeki Matsumoto, Satyanarayan Mukhopadhyay, Mihoko M. Nojiri
JHEP10(2013)032 2013年6月 [査読有り]
Asymmetric dark matter (ADM) has been an attractive possibility attempting to
explain the observed ratio of baryon to dark matter abundance in the universe.
While a bosonic ADM is constrained by the limits from existence of old neutron
stars, a fe...
Motivated by future collider proposals that aim to measure the Higgs
properties precisely, we study the partial decay widths of the lightest Higgs
boson in the minimal supersymmetric standard model with an emphasis on the
parameter region where al...
Sourav K. Mandal, Mihoko Nojiri, Matthew Sudano, Tsutomu T. Yanagida, .
JHEP 1101(131) 2011年
The hierarchy of the Yukawa couplings is an outstanding problem of the
standard model. We present a class of models in which the first and second
generation fermions are SUSY partners of pseudo-Nambu-Goldstone bosons that
parameterize a non-compac...
In a class of Randall-Sundrum(RS) models, matter fermions and gauge bosons
live in a five dimensional bulk, while the Higgs boson lives in a four
dimensional visible brane. The Higgs boson can mix with a radion, by a
Higgs-radion mixing term. It i...
Present experimental datas have shown a 3.8 level discrepancy with
the standard model in . Some new
physics models have been considered to explain this discrepancy possibly with
new source of th...
Ben Gripaios, Keiko Nagao, Mihoko Nojiri, Kazuki Sakurai, Bryan Webber
JHEP 03(2013)106 2012年10月 [査読有り]
We propose a method for reconstructing the mass of a particle, such as the
Higgs boson, decaying into a pair of tau leptons, of which one subsequently
undergoes a 3-prong decay. The kinematics is solved using information from the
visible decay pro...
Keisuke Harigaya, Shigeki Matsumoto, Mihoko M. Nojiri, Kohsaku Tobioka
2012年4月
Vector-like quarks are introduced in various new physics models beyond the
standard model (SM) at the TeV scale. We especially consider the case that the
quark is singlet (triplet) under the SU(2) (SU(3)) gauge group and
couples only to th...
Biplob Bhattacherjee, Sourav K. Mandal, Mihoko Nojiri
JHEP 1303 (2013) 105 2012年11月 [査読有り]
Top polarization is an important probe of new physics that couples to the top
sector, and which may be discovered at the 14 TeV LHC. Taking the example of
the MSSM, we argue that top polarization measurements can put a constraint on
the soft super...
Sung-Gi Kim, Nobuhiro Maekawa, Keiko I. Nagao, Mihoko M. Nojiri, Kazuki Sakurai
JHEP 0910:005,2009 0910(005) 2009年7月
We study the LHC signature of the minimal supersymmetric standard model with
non-universal sfermion masses. In the model, soft masses of gauginos and the
3rd generation of 10 of SU(5) are around the weak scale, while other sfermion
soft mass is un...
Keisuke Harigaya, Shigeki Matsumoto, Mihoko M. Nojiri, Kohsaku Tobioka
2011年9月
In the framework of the little higgs scenario, coupling constants of several
interactions are related to each other to guarantee the stability of the higgs
boson mass at one-loop level. This relation is called the little higgs
mechanism. We discus...
Subhaditya Bhattacharya, Sanjoy Biswas, Biswarup Mukhopadhyaya, Mihoko M. Nojiri
2011年5月
We discuss large non-universality in the Higgs sector at high scale in
supersymmetric theories, in the context of the Large Hadron Collider (LHC). In
particular, we note that if is large and negative
($\simeq 10^6 {\rm ~G...
In this paper we study the higgs-radion system of the Randall-Sundum model
where matter and gauge fields live in the bulk. We take into account the
Kalza-Klein(KK) loop correction for the higgs and the raidion coupling to the
gauge bosons. Inspire...
Chuan-Ren Chen, Mihoko M. Nojiri, Seong Chan Park, Jing Shu, Michihisa Takeuchi
JHEP 0909:078,2009 0909(078) 2009年3月
We explicitly show that split-universal extra dimension (split-UED), a
recently suggested extension of universal extra dimension (UED) model, can
nicely explain recent anomalies in cosmic-ray positrons and electrons observed
by PAMELA and ATIC/PPB...
Chuan-Ren Chen, Mihoko M. Nojiri, Seong Chan Park, Jing Shu
2009年8月
Kaluza-Klein photon in universal extra dimension models is one of the most
attractive dark matter candidates as a weakly interacting massive particle.
Having a characteristic split spectrum in split universal extra dimension the
relic density of K...
Keisuke Harigaya, Shigeki Matsumoto, Mihoko M. Nojiri, Kohsaku Tobioka
JHEP 1201 (2012) 135 2011年9月 [査読有り]
In the framework of the little higgs scenario, coupling constants of several
interactions are related to each other to guarantee the stability of the higgs
boson mass at one-loop level. This relation is called the little higgs
mechanism. We discus...
We report a new possibility of using the (Constransverse mass)
variable for mass measurement in single step decay chains involving missing
particles with moderate transverse momentum. We show that its experimental
feasibility is enhanced c...
Hitoshi Murayama, Mihoko M. Nojiri, Kohsaku Tobioka
PhysRevD.84:094015,2011 2011年7月 [査読有り]
We study the discovery potential of the Minimal Universal Extra Dimension
model (MUED) and improve it utilizing the multijet + lepton mode at the LHC.
Since the MUED has a nearly degenerate spectrum, most events only have soft
jets and small Emiss...
A method is proposed for determining the masses of the new particles N,X,Y,Z
in collider events containing a pair of effectively identical decay chains Z to
Y+jet, Y to X+l_1, X to N+l_2, where l_1, l_2 are opposite-sign same-flavour
charged lepto...
We argue that we may be able to sort out dark matter models in which
electrons are generated through the annihilation and/or decay of dark matter,
by using a fact that the initial energy spectrum is reflected in the cosmic-ray
electron flux observ...
Chuan-Ren Chen, Mihoko M. Nojiri, Warintorn Sreethawong
JHEP 1011(012) 2010年6月
We consider the production of a light non-standard model Higgs boson of order with an associated boson at CERN Large Hadron Collider. We focus
on an interesting scenario that, the Higgs boson decays predominately into two
light scal...
We consider the spin determination of new colored particles in the missing
energy plus jets channel at the early stage of LHC. We use a three site moose
model to describe the low energy Lagrangian of all same spin partner (LHT or
UED like) models ...
Johan Alwall, Kenji Hiramatsu, Mihoko M. Nojiri, Yasuhiro Shimizu
Phys.Rev.Lett.103:151802,2009 103(151802) 2009年5月
At hadron colliders, the production of heavy new particles is associated with
additional quarks and gluons with significant transeverse momentum. The
additional jets complicates the reconstruction of new particle masses. Taking
gluino pair product...
Chuan-Ren Chen, Mihoko M. Nojiri, Fuminobu Takahashi, T. T. Yanagida
Prog.Theor.Phys.122:553-559,2009 2008年11月
We show that the PAMELA anomaly in the positron fraction as well as the
ATIC/PPB-BETS excesses in the e^- + e^+ flux are simultaneously explained in
our scenario that a hidden U(1)H gauge boson constitutes dark matter of the
Universe and decays in...
Use of inclusive MT2 distribution for sparticle mass determination is
discussed. We define new parameters MT2(min) and MT2mod(min), which are a kind
of minimum of sub-systerm MT2 values. Their endpoints are less affected by
initial state radiation...
We investigate the observed spectrum of cosmic-ray electrons and positrons
from astrophysical sources, especially pulsars, and the physical processes for
making the spectrum spiky or smooth via continuous and multiple
electron/positron injections....
Mihoko M. Nojiri, Kazuki Sakurai, Yasuhiro Shimizu, Michihisa Takeuchi
JHEP0810:100,2008 2008年8月
The ATLAS and CMS experiments at the Large Hadron Collider (LHC) may discover
the squarks (\tilde{q}) and gluino (\tilde{g}) of the minimal supersymmetric
standard model (MSSM) in the early stage of the experiments if their masses are
lighter than...
Mihoko M. Nojiri, Yasuhiro Shimizu, Shogo Okada, Kiyotomo Kawagoe
JHEP0806:035,2008 2008年2月
We propose an inclusive analysis of a stransverse mass (m_{T2}) using a
hemisphere method for supersymmetry studies at the LHC . The hemisphere method
is an algorithm to group collinear and high p_T particles and jets, assuming
that there are two ...
Junji Hisano, Mihoko M. Nojiri, Warintorn Sreethawong
JHEP 0906:044,2009 0906(044) 1 2008年12月
Current limit on the dark matter relic abundance may suggest that
should be smaller than prediction in the minimal supergravity scenario (mSUGRA)
for moderate and . The electroweak-ino parameter and are th...
I review recent developments on the use of mT2 variables for SUSY parameter
study, which might be useful for the data analysis in the early stage of the
LHC experiments. I also review some of recent interesting studies. Talk in
SUSY08.
The lighter chargino pair production () is one of key processes for determination of
supersymmetric parameters at a linear collider. If is a large
value, the lighter stau ($\tilde{\...
In the Littlest Higgs model with T-parity (LHT), top-partners (T_-) are
produced in pairs at the Large Hadron Collider (LHC). Each top-partner decays
into a top quark (t) and the lightest T-odd gauge partner A_H. We demonstrate
reconstruction of t...
Koichi Hamaguchi, Mihoko M. Nojiri, Albert de Roeck
JHEP 0703:046,2007 2006年12月
If the scalar tau is the next lightest supersymmetric particle and
decays into a gravitino () being the lightest supersymmetric
particle, it will have generally a very long lifetime. In this paper, we
investigate the possibilit...
production is one of the main SUSY production
processes in the MSSM, which occurs due to the chirality flip caused by the
Majorana gluino mass. This process is one of the sources of same sign two
lepton (SS2) events, h...
Shigeki Matsumoto, Mihoko M. Nojiri, Daisuke Nomura
Phys.Rev.D75:055006,2007 2006年12月
We study the Littlest Higgs model with T-parity at the LHC through pair
productions of the T-odd top quark partner (T_-) which decays into the top
quark and the lightest T-odd particle. We identify the region of parameters
favored by the electrowe...
Junji Hisano, Minoru Nagai, Mihoko M. Nojiri, Masato Senami
Phys.Rev. D73 (2006) 031701 2005年4月
We investigate a possibility of neutralino dark matter (DM) direct detection
in the future electron accelerators. That is counting of high p_T electron
recoil events by neutralinos in halo. If selectron and neutralino masses would
be precisely mea...
Discovery of supersymmetric (SUSY) particles at the Large Hadron
Collider(LHC) has been studied for the models where squarks and gluino are much
heavier than the lightest supersymetric particle (LSP). In this paper, we
investigate the SUSY discove...
Junji Hisano, Shigeki. Matsumoto, Mihoko M. Nojiri, Osamu Saito
Phys.Rev. D71 (2005) 063528 2004年12月
Detection of gamma rays from dark matter annihilation in the galactic center
is one of the feasible techniques to search for dark matter. We evaluate the
gamma ray flux in the case that the dark matter has an electroweak SU(2)_L
charge. Such dark ...
Junji Hisano, Shigeki Matsumoto, Mihoko M. Nojiri, Osamu Saito
Phys.Rev. D71 (2005) 015007 D71: 015007 2004年7月
The neutralino-nucleon (\tilde{\chi}^0-N) scattering is an important process
for direct dark matter searches. In this paper we discuss one-loop
contributions to the cross section in the wino-like and Higgsino-like LSP
cases. The neutralino-nucleon...
Koichi Hamaguchi, Yoshitaka Kuno, Tsuyoshi Nakaya, Mihoko M. Nojiri
Phys.Rev.D70:115007,2004 D70: 115007 2004年9月
In models where the gravitino is the lightest supersymmetric particle (LSP),
the next-to-lightest supersymmetric particle (NLSP) is long-lived. We consider
an important charged NLSP candidate, the scalar tau . Slow
charged NLSPs may ...
At the LHC, superpartners with the masses lighter than a few TeV may be
found, and the masses of the supersymmetric (SUSY) particles and their
interactions will be studied. The information would be the base to consider the
SUSY breaking mechanism ...
Junji Hisano, Kiyotomo Kawagoe, Ryuichiro Kitano, Mihoko M. Nojiri
Phys.Rev. D66 (2002) 115004 D66:115004 2002年4月
In the minimal supersymmetric standard model (MSSM) properties of the third
generation sfermions are important from the viewpoint of discriminating the
SUSY breaking models and in the determination of the Higgs boson mass. If
gluinos are copiously...
Kiyotomo Kawagoe, Tomio Kobayashi, Mihoko M. Nojiri, Atsuhiko Ochi
Phys.Rev. D69 (2004) 035003 D69:035003 2003年9月
In this paper we study the gauge mediation signal with the ATLAS detector at
the CERN LHC. We focus on the case where the NLSP is the long-lived lightest
neutralino () which decays dominantly into a photon
() and a gravit...
SUSY PARAMETER DETERMINATION IN COMBINED ANALYSES AT LHC / LC.
Journal of High Energy Physics 0402:035 2004年
STUDY OF THE SLEPTON NON-UNIVERSALITY AT THE CERN LARGE HADRON COLLIDER.
If the Dark Matter (DM) in the Universe has interactions with the
standard-model particle, the pair annihilation may give the imprints in the
cosmic ray. In this paper we study the pair annihilation processes of the DM,
which is neutral, however h...
Manuel Drees, Yeong Gyun Kim, Tatsuo Kobayashi, Mihoko M. Nojiri
Phys.Rev.D63:115009,2001 (D63) 115009 2000年11月
We compare predictions for the spin-independent contribution to the
neutralino-proton scattering cross section and for the anomalous
magnetic dipole moment of the muon, , in models with
gravity-mediated supersymmetry br...
In supersymmetric models a gluino can decay into
through a stop or a sbottom. The decay chain produces an edge structure in the distribution. Monte Carlo simulation studies show that the end point
and the edge hei...
Manuel Drees, Yeong Gyun Kim, Mihoko M. Nojiri, Daisuke Toya, Kazumi Hasuko, Tomio Kobayashi
Phys.Rev.D63:035008,2001 2000年7月
We show that LHC experiments might well be able to determine all the
parameters required for a prediction of the present density of thermal LSP
relics from the Big Bang era. If the LSP is an almost pure bino we usually only
need to determine its m...
In supersymmetric models a gluino can decay into tb\tilde{\chi}^{\pm}_1
through a stop or a sbottom. The decay chain produces an edge structure in the
m_{tb} distribution. Monte Carlo simulation studies show that the end point and
the edge height ...
The neutralino pair annihilation into two photons in our galactic halo gives
a robust dark matter signal, since it would give a quasi-monotonic gamma ray.
This process is radiatively-induced, and the full-one loop calculation was done
previously. ...
We present a pedagogical introduction to supersymmetry and supersymmetric
models and give an overview of the potential of the linear collider for
studying them. If supersymmetry is found, its discovery will bring with it many
more questions than a...
Measurement of Lepton-Flavor Violation (LFV) in the minimal SUSY Standard
Model (MSSM) at Large Hadron Collider (LHC) is studied based on a realistic
simulation. We consider the LFV decay of the second-lightest neutralino,
$\tilde{\chi}^0_2 \to \t...
We investigate the implications of the recent measurement of muon anomalous
magnetic moment for the direct detection of neutralino dark matter in the three
different SUSY models: mSUGRA, a model with non-universal Higgs mass, and an
SO(10) GUT mod...
Junji Hisano, Mihoko M. Nojiri, Yasuhiro Shimizu, Minoru Tanaka
Phys.Rev. D60 (1999) 055008 1998年8月
The Super-Kamiokande atmospheric neutrino data suggest existence of the large
lepton-flavor violating (LFV) interaction in the higher energy scale. If the
minimal supersymmetric standard model is extended to have right-handed
neutrinos, the left-h...
The gauge-mediated SUSY-breaking (GMSB) model needs entropy production at a
relatively low temperature in the thermal history of the Universe for the
unwanted relics to be diluted. This requires a mechanism for the baryogenesis
after the entropy p...
We show that LHC experiments might well be able to determine all the parameters required for a prediction of the present density of thermal LSP relics from the Big Bang era. If the LSP is an almost pure bino we usually only need to determine its m...
Shingo Kiyoura, Mihoko M. Nojiri, Damien M. Pierce, Youichi Yamada
Phys.Rev. D58 (1998) 075002 58 075002 1998年3月
Recently it has been realized that the production and decay processes of
charginos, neutralinos, and sleptons receive corrections which grow like log
m_squark for large m_squark. In this paper we calculate the chargino pair
production cross sectio...
We study the distribution of lepton pairs from the second lightest neutralino
decay \tilde{\chi}^0_2-->\tilde{l}l followed by \tilde{l}\to \tilde{\chi}^0_1
l. The distribution of the ratio of lepton transverse momenta A_T shows peak
structure if m...
1)LHC実験においては、重たい粒子の生成にともなって、かなりハードなinitial state radiationがおこる。このinitial state radiationはpartonの種類によって異なる分布をとる。このISRの分布を細かく研究し、ハードプロセスとの違いを明らかにした。この分布からISRを除く最適のカットを開発し、超対称粒子の質量のMT2分布に表れend pointを崩壊形式によらずに求める方法を明らかにした。2)一つのクオークやグルーオンから作られるジェットはケンブ...
LHC実験では標準模型を越える粒子が生成され、その崩壊が観測されると期待されている。このような模型の中でも、超対称模型に代表される暗黒物質の候補ををもつ模型についてLHC実験によって、新粒子の質量・相互作用を測定する方法について研究を行い、MT2の活用、end pointに寄らない質量決定法、Initial state radiationの除去法等について成果をあげた。
