Rare Decays

We compute the branching ratios for the radiative rare decays of B into K-Meson states and compare them to the experimentally determined branching ratio for inclusive decay b → sγ using non relativistic quark model, and form factor definitions consistent with HQET covariant trace formalism. Such calculations necessarily involve a potential model. In order to test the sensitivity of calculations to potential models we have used three different potentials, namely linear potential, screening confining potential and heavy quark potential as it stands in QCD.We find the branching ratios relative to the inclusive b → sγ decay to be (16.07±5.2)% for B → K ⋆ (892)γ and (7.25±3.2)% for B → K ⋆ 2 (1430)γ for linear potential. In the case of the screening confining potential these values are (19.75 ± 5.3)% and (4.74 ± 1.2)% while those for the heavy quark potential are (11.18 ± 4.6)% and (5.09 ± 2.7)% respectively. All these values are consistent with the corresponding present CLEO experimental values: (16.25 ± 1.21)% and (5.93 ± 0.46)%.

The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described. KEYWORDS: Large detector systems for particle and astroparticle physics; Particle tracking detectors; Gaseous detectors; Calorimeters; Cherenkov detectors; Particle identification methods; Photon detectors for UV, visible and IR photons; Detector alignment and calibration methods; Detector cooling and thermo-stabilization; Detector design and construction technologies and materials.

The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described. KEYWORDS: Large detector systems for particle and astroparticle physics; Particle tracking detectors; Gaseous detectors; Calorimeters; Cherenkov detectors; Particle identification methods; Photon detectors for UV, visible and IR photons; Detector alignment and calibration methods; Detector cooling and thermo-stabilization; Detector design and construction technologies and materials.

We present a search for the avor-changing neutral current decays B 0 d ! + , and B 0 s ! + , in p p collisions at p s = 1:8 TeV, using 98 pb ,1 of data collected at the Collider Detector at Fermilab CDF. We nd one candidate event for these decays, which is consistent with the background estimates, and set upper limits on the branching fractions of BB 0 d ! + , 8:6 10 ,7 and BB 0 s ! + , 2:6 10 ,6 at 95 con dence level.

Despite the success of the Standard Model (SM), which provides a superb description of a wide range of experimental particle physics data, the dynamics responsible for electroweak symmetry breaking is still unknown. Its elucidation remains one of the primary goals of future high energy physics experimentation. Present day global fits to precision electroweak data based on the Standard Model favor the existence of a weakly-interacting scalar Higgs boson, which is a remnant of elementary scalar dynamics that drives electroweak symmetry breaking. The only known viable theoretical framework incorporating light elementary scalar fields employs "low-energy" supersymmetry, where the scale of supersymmetry breaking is O(1 TeV). The Higgs sector of the Minimal Supersymmetric extension of the Standard Model (MSSM) is of particular interest because it predicts the existence of a light CP-even neutral Higgs boson with a mass below about 130 GeV. Moreover, over a significant portion of the MSSM parameter space, the properties of this scalar are indistinguishable from those of the SM Higgs boson. In Run 2 at the Tevatron, the upgraded CDF and DØ experiments will enjoy greatly enhanced sensitivity in the search for the SM Higgs boson and the Higgs bosons of the MSSM. This report presents the theoretical analysis relevant for Higgs physics at the Tevatron collider and documents the Higgs Working Group simulations to estimate the discovery reach of an upgraded Tevatron for the SM and MSSM Higgs bosons. Based on a simple detector simulation, we have determined the integrated luminosity necessary to discover the SM Higgs in the mass range 100-190 GeV. The first phase of the Run 2 Higgs search, with a total integrated luminosity of 2 fb -1 per detector, will provide a 95% CL exclusion sensitivity comparable to that expected at the end of the LEP2 run. With 10 fb -1 per detector, this exclusion will extend up to Higgs masses of 180 GeV, and a tantalizing 3σ effect will be visible if the Higgs mass lies below 125 GeV. With 25 fb -1 of integrated luminosity per detector, evidence for SM Higgs production at the 3σ level is possible for Higgs masses up to 180 GeV. However, the discovery reach is much less impressive for achieving a 5σ Higgs boson signal. Even with 30 fb -1 per detector, only Higgs bosons with masses up to about 130 GeV can be detected with 5σ significance. These results can also be re-interpreted in the MSSM framework and yield the required luminosities to discover at least one Higgs boson of the MSSM Higgs sector. With 5-10 fb -1 of data per detector, it will be possible to exclude at 95% CL nearly the entire MSSM Higgs parameter space, whereas 20-30 fb -1 is required to obtain a 5σ Higgs discovery over a significant portion of the parameter space. Moreover, in one interesting region of the MSSM parameter space (at large tan β), the associated production of a Higgs boson and a b b pair is significantly enhanced and provides potential for discovering a non-SM-like Higgs boson in Run 2. Further studies related to charged Higgs boson searches and exploiting other search modes of the neutral Higgs bosons are underway and may enhance the above discovery potential.

We consider the structure-dependent amplitude of the decay B s → l + l -γ (l = e, µ) in a model based on the effective Hamiltonian for bs → l + l -containing the Wilson coefficients C 7 , C 9 and C 10 . The form factors characterising the matrix elements γ|sγ µ (1 ∓ γ 5 )b| Bs and γ|sσ µν (1 ∓ γ 5 )b| Bs are taken to have the universal form f V ≈ f A ≈ f T ≈ f Bs M Bs R s /(3E γ ) suggested by recent work in QCD, where R s is a parameter related to the light cone wave function of the B s meson. Simple expressions are obtained for the charge asymmetry A(x γ ) and the photon energy spectrum dΓ/dx γ (x γ = 2E γ /M Bs ). The decay rates are calculated in terms of the decay rate of B s → γγ. The branching ratios are estimated to be Br(B s → e + e -γ) = 2.0 × 10 -8 and Br(B s → µ + µ -γ) = 1.2 × 10 -8 , somewhat higher than earlier estimates.

The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described. KEYWORDS: Large detector systems for particle and astroparticle physics; Particle tracking detectors; Gaseous detectors; Calorimeters; Cherenkov detectors; Particle identification methods; Photon detectors for UV, visible and IR photons; Detector alignment and calibration methods; Detector cooling and thermo-stabilization; Detector design and construction technologies and materials.

A search for the decay $ K_{\mathrm{S}}^0\to {\mu^{+}}{\mu^{-}} $ is performed, based on a data sample of 1.0 fb−1 of pp collisions at $ \sqrt{s}=7\;\mathrm{TeV} $ collected by the LHCb experiment at the Large Hadron Collider. The observed number of candidates is consistent with the background-only hypothesis, yielding an upper limit of $ \mathcal{B}\left( {K_{\mathrm{S}}^0\to {\mu^{+}}{\mu^{-}}} \right) $ < 11(9) × 10−9 at 95 (90)% confidence level. This limit is a factor of thirty below the previous measurement.

After incorporating all the available experimental data and the most up-to-date Lattice and light cone sum rule (LCSR) inputs on the form factors, we analyze the exclusive b → uℓνℓ and b → dℓℓ decays simultaneously. We have extracted the shapes of all the associated form factors using which we have provided predictions in the standard model for the branching ratios, direct CP asymmetries and isospin asymmetry for B → πℓℓ and various angular observables for B → ρℓℓ transitions. Also, we have tested the sensitivities of these observables towards physics beyond the standard model (BSM). For the B → ρℓℓ decays, we have defined tagged and untagged observables and predicted them in the SM and BSM. In the context of BSM, we have found some compelling information. The respective predictions in a few benchmark scenarios are given, which can be tested in the experiments at the LHCb and the Belle.

A search for fully reconstructed 0 b beauty baryons is performed using about 3 million Z decays collected with the DELPHI detector at LEP. The analysis relies on the combined use of the accurate tracking and of the hadron identication capabilities of DELPHI. A total of four events has been found, three in the + c channel and one in the + c a 1 channel over a small background. The 0 b beauty baryon mass is measured to be ( 5668 16 (stat:) 8 (syst:) ) MeV/c 2 .

We present evidence for the b ! d penguin-dominated decays B ! K 0 K and B 0 ! K 0 K 0 in 227 10 6 4S ! B B decays collected with the BABAR detector. We measure the branching fractions BB ! K 0 K 1:5 0:5 0:1 10 ÿ6 <2:4 10 ÿ6 and BB 0 ! K 0 K 0 1:19 0:40 ÿ0:35 0:13 10 ÿ6 , where the uncertainties are statistical and systematic, respectively. We also present improved measurements of the charge-averaged branching fraction BB ! K 0 26:0 1:3 1:0 10 ÿ6 and CP-violating charge asymmetry A CP K 0 ÿ0:09 0:05 0:01, where the uncertainties are statistical and systematic, respectively.

We report a search for the rare decays B + → D + K 0 and B + → D + K * 0 in an event sample of approximately 465 million BB pairs collected with the BABAR detector at the PEP-II asymmetricenergy e + e -collider at SLAC. We find no significant evidence for either mode and we set 90% probability upper limits on the branching fractions of B(B + → D + K 0 ) < 2.9 × 10 -6 and B(B + → D + K * 0 ) < 3.0 × 10 -6 .

We present measurements of CP-violating asymmetries and branching fractions for the decays B ! ! , B ! !K , and B 0 ! !K 0 . The data sample corresponds to 232 10 6 B B pairs produced by e e ÿ annihilation at the 4S resonance. For the decay B 0 ! !K 0 S , we measure the time-dependent

A search for the rare decay mode KL x yy was performed using a data set from Fermilab experi- ment E-731. The decay is of interest in the context of chiral perturbation theory and for its contribution to the decay KL tr e+e . The result is 8(KL tr yy) (2.7x10 (90% confidence level) which is nearly a two-order-of-magnitude improvement over the previous best limit.

We have studied two-body charmless decays of the B meson into the final states ρ 0 ρ 0 , K * 0 ρ 0 , K * 0 K * 0 , K * 0 K * 0 , K * + ρ 0 , K * + K * 0 , and K * + K * -using only decay modes with charged daughter particles. Using 9.7 million B B pairs collected with the CLEO detector, we place 90% confidence level upper limits on the branching fractions, (0.46 -7.0) × 10 -5 , depending on final state and polarization.

The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear $e^+e^−$ collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. For an optimal exploitation of its physics potential, CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively, for a site length ranging from 11 km to 50 km. CLIC uses a two-beam acceleration scheme, in which normal-conducting high-gradient 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in significant progress in recen...

Since april 1999, the KLOE experiment at DAFNE has collected about 200 inverse pb of data, produced in electron-positron collision at the c.m. energy of 1020 MeV, the mass of the phi meson. These data have been used for detailed studies on the phi radiative decays, as well as on rare K short decays. The first results, based on the 20 inverse pb collected in year 2000 are presented here

We use MasterCode to perform a frequentist analysis of the constraints on a phenomenological MSSM model with 11 parameters, the pMSSM11, including constraints from ∼ 36/fb of LHC data at 13 TeV and PICO, XENON1T and PandaX-II searches for dark matter scattering, as well as previous accelerator and astrophysical measurements, presenting fits both with and without the (g-2) μ constraint. The pMSSM11 is specified by the following parameters: 3 gaugino masses M 1,2,3 , a common mass for the first-and second-generation squarks m q and a distinct third-generation squark mass m q3 , a common mass for the first-and second-generation sleptons m ˜ and a distinct third-generation slepton mass m τ , a common trilinear mixing parameter A, the Higgs mixing parameter μ, the pseudoscalar Higgs mass M A and tan β. In the fit including (g -2) μ , a Bino-like χ 0 1 is preferred, whereas a Higgsino-like χ 0 1 is mildly favoured when the (g -2) μ constraint is dropped. We identify the mechanisms that operate in different regions of the pMSSM11 parameter space to bring the relic density of the lightest neutralino, χ 0 1 , into the range indicated by cosmological data. In the fit including (g -2) μ , coannihilations with χ 0 2 and the Wino-like χ ±

We study the prospects of searches for exotic long-lived particles with the MoEDAL detector at the LHC, assuming the integrated luminosity of 30 fb -1 that is expected at the end of Run 3. MoEDAL incorporates nuclear track detectors deployed a few metres away from the interaction point, which are sensitive to any highly-ionizing particles. Hence MoEDAL is able to detect singly-or doublycharged particles with low velocities β < 0.15 or < 0.3, respectively, and lifetimes larger than O(1) m/c. We examine the MoEDAL sensitivity to various singly-charged supersymmetric particles with long lifetimes and to several types of doubly-charged long-lived particles with different spins and SU(2) charges. We compare the prospective MoEDAL mass reaches to current limits from ATLAS and CMS, which involve auxiliary analysis assumptions. MoEDAL searches for doubly-charged fermions are particularly competitive.

An analytical formalism, including RG running at two loop order, is used to link the supersymmetric and GUT spectra in any GUT model in which the three gauge couplings unify. In each specific GUT model, one can then fully explore the interplay between the pattern of supersymmetry breaking and the prediction for the proton lifetime. With this formalism at hand, we study three concrete GUT models: (i) Minimal SU(5) SUSY GUT, (ii) Missing Partner SU(5) SUSY GUT, and (iii) an orbifold SU(5) SUSY GUT. In each case we derive interesting conclusions about the possible patterns of the supersymmetric spectrum once the present limits on the proton lifetime are imposed, and vice versa, we obtain the predictions for the proton lifetime for specific viable choices of the SUSY spectrum.

We investigate monotop signatures arising from phenomenological models of fermionic top partners, which are degenerate in mass and decay into a bosonic dark matter candidate, either spin 0 or spin 1. Such a model provides a monotop signature as a smoking gun, while conventional searches with t tþ missing transverse momentum are limited. Two such scenarios, (i) a phenomenological third generation extradimensional model with excited top and electroweak sectors, and (ii) a model where only a top partner and a dark matter particle are added to the standard model, are studied in the degenerate mass regime. We find that in the case of extra dimension a number of different processes give rise to effectively the same monotop final state, and a great gain can be obtained in the sensitivity for this channel. We show that the monotop search can explore top-partner masses up to 630 and 300 GeV for the third generation extradimensional model and the minimal fermionic top-partner model, respectively, at the high luminosity LHC.

The angular distributions and the partial branching fraction of the decay B 0 ! K Ã0 þ À are studied by using an integrated luminosity of 0:37 fb À1 of data collected with the LHCb detector. The forwardbackward asymmetry of the muons, A FB , the fraction of longitudinal polarization, F L , and the partial branching fraction dB=dq 2 are determined as a function of the dimuon invariant mass. The measurements are in good agreement with the standard model predictions and are the most precise to date. In the dimuon invariant mass squared range 1:00-6:00 GeV 2 =c 4 , the results are A FB ¼ À0:06 þ0:13 À0:14 AE 0:04, F L ¼ 0:55 AE 0:10 AE 0:03, and dB=dq 2 ¼ ð0:42 AE 0:06 AE 0:03Þ Â 10 À7 c 4 =GeV 2 . In each case, the first error is statistical and the second systematic.

We investigate the possibility that a (light) hidden sector extra photon receives its mass via spontaneous symmetry breaking of a hidden sector Higgs boson, the so-called hidden-Higgs. The hidden-photon can mix with the ordinary photon via a gauge kinetic mixing term. The hidden-Higgs can couple to the Standard Model Higgs via a renormalizable quartic termsometimes called the Higgs Portal. We discuss the implications of this light hidden-Higgs in the context of laser polarization and light-shining-through-the-wall experiments as well as cosmological, astrophysical, and non-Newtonian force measurements. For hidden-photons receiving their mass from a hidden-Higgs we find in the small mass regime significantly stronger bounds than the bounds on massive hidden sector photons alone.

We analyze the semileptonic B → K * 2 (1430)l + l -transition in universal extra dimension model. In particular, we present the sensitivity of related observables such as branching ratio, polarization distribution and forward-backward asymmetry to the compactification factor (1/R) of extra dimension. The obtained results from extra dimension model show overall a considerable deviation from the standard model predictions for small values of the compactification factor. This can be considered as an indication for existence of extra dimensions.

We obtain a lower limit on the compactification scale of extra dimension via comparison of the branching ratio in the baryonic Λ b → Λµ + µ -decay channel recently measured by CDF collaboration and our previous theoretical study. We also use the newly available form factors calculated via light cone QCD sum rules in full theory to analyze the flavour changing neutral current process of the Σ b → Σℓ + ℓ -in universal extra dimension scenario in the presence of a single extra compact dimension. We calculate various physical quantities like branching ratio, forward-backward asymmetry, baryon polarizations and double lepton polarization asymmetries defining the decay channel under consideration. We also compare the obtained predictions with those of the standard model.

We work out the semileptonic Λ b → Λℓ + ℓ -transition in standard as well as different supersymmetric models. In particular, considering the parametrization of the matrix elements entered the low energy effective Hamiltonian in terms of form factors in full QCD, we calculate the amplitude and differential decay rate responsible for this decay channel in supersymmetric models. We then use the form factors calculated via light cone QCD sum rules in full theory to analyze the differential branching ratio and lepton forward-backward asymmetry of this decay channel in different supersymmetric models and compare the obtained results with those of the standard model. We also discuss how the results of different supersymmetric models deviate from the standard model predictions and which SUSY scenarios are favored.

Linac-ring type colliders will open new windows for both energy frontier and particle factories. Concerning the first direction, these machines seem to be a sole way to TeV scale in lepton-hadron collisison at constituent level. An essential advantage of the linac-ring type lepton-hadron colliders is the possibility of the construction of γp, γA and FELγ-A colliders based on them. Today, eRHIC, THERA (TESLA on HERA) and Linac*LHC can be considered as realistic candidates for future lepton-hadron and photon hadron colliders. When it comes to factories, one can reach essentially higher luminosities comparing to standard ring-ring type machines. For example, L=10 34 cm -2 s -1 can be achieved for phi and charm-tau factories. In this presentation we briefly discuss the parameters and physics search potential of the linac-ring type machines.

Main parameters of the linac-ring type charm-tau factory are discussed. Different sets of parameters for an electron linac and a positron ring have been considered. It is shown that L=10^33 cm-2 s-1 and even more can be achieved. The physics goals of this machine in investigation for charmed particles and tau lepton properties are briefly discussed. Advantages of the proposed machine in comparison with standard (ring-ring) type charm-tau factory proposals will be the possibility of the search for rare decays of tau lepton and charm quark and study of D^0-D^-0 oscillations.

We present the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our report includes new agreements on formats for interfaces between computational tools, new tool developments, important signatures for searches at the LHC, recommendations for presentation of LHC search results, as well as additional phenomenological studies.

We report an analysis of charmless hadronic decays of neutral B mesons to the final state K 0 S K AE Ç , using a data sample of ð465 AE 5Þ Â 10 6 B " B events collected with the BABAR detector at the Çð4SÞ resonance. We observe an excess of signal events with a significance of 5.2 standard deviations including systematic uncertainties and measure the branching fraction to be BðB 0 ! K 0 S K AE Ç Þ ¼ ð3:2 AE 0:5 AE 0:3Þ Â 10 À6 , where the uncertainties are statistical and systematic, respectively.

A method to extract Standard Model(SM) CP phases involving B decays is presented. The method involves a pair of decays where one decay receives a significant $b \to d$ penguin contribution while the second has a significant $b \to s$ penguin contribution, but is dominated by a single amplitude. SM CP phase information is obtained using the fact that the $b \to s$ transition amplitude is related by SU(3) to a piece of the amplitude with the $b \to d$ transition. If there is significant new physics only in $b \to s$ transitions and not in $b \to d$ transitions then this method can be used to measure new physics(NP) phases.

A search for the decay K_S -&gt; pi0e+e- has been made by the NA48/1 experiment at the CERN SPS accelerator. Using data collected during 89 days in 2002 with a high-intensity K_S beam, 7 events were found with a background of 0.15 events. The branching fraction BR(K_S -&gt; pi0e+e-, m_ee &gt; 0.165GeV/c2) = (3.0^+1.5_1.2(stat) +- 0.2(syst)) x 10^-9 has been

A search for the decay $\kspiee$ has been made using the NA48 detector at the CERN SPS. Using data collected in 1999 during a 40-hour run with a high-intensity $\ks$ beam, an upper limit for the branching fraction ${\rm B}(\kspiee) &lt; 1.4 \times 10^{-7}$ at 90\% confidence level has been obtained. %Extrapolating this limit to the full phase-space %assuming the

We measure the ratio of branching fractions for the ϒð4SÞ decays to B þ B -and B 0 B0 using B þ → J=ψðllÞK þ and B 0 → J=ψðllÞK 0 samples, where J=ψðllÞ stands for J=ψ → l þ l -(l ¼ e or μ), with 711 fb -1 of data collected at the ϒð4SÞ resonance with the Belle detector. We find the decay rate ratio of ϒð4SÞ → B þ B -over ϒð4SÞ → B 0 B0 to be 1.065 AE 0.012 AE 0.019 AE 0.047, which is the most precise measurement to date. The first and second uncertainties are statistical and systematic, respectively, and the third uncertainty is due to the assumption of isospin symmetry in B → J=ψðllÞK.

The primary physics goals of a high luminosity e+e- flavor factory are discussed, including the possibilities to perform detailed studies of the CKM mechanism of quark mixing, and constrain virtual Higgs and non-standard model particle contributions to the dynamics of rare B_{u,d,s} decays. The large samples of D mesons and tau leptons produced at a flavor factory will result in

The difference between induced by box diagram value o and experimentally measured value of is estimated. It appeared to be around 5 − 10%, depending on the values of hadronic matrix elements. With this result, the fit of CKM marix parameters within the SM is performed.

The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community to explore the Higgs boson and provide critical tests of the underlying fundamental physics principles of the Standard Model that might reveal new physics. The CEPC, to be hosted in China in a circular underground tunnel of approximately 100 km in circumference, is designed to operate as a Higgs factory producing electron-positron collisions with a center-of-mass energy of 240 GeV. The collider will also operate at around 91.2 GeV, as a Z factory, and at the WW production threshold (around 160 GeV). The CEPC will produce close to one trillion Z bosons, 100 million W bosons and over one million Higgs bosons. The vast amount of bottom quarks, charm quarks and tau-leptons produced in the decays of the Z bosons also makes the CEPC an effective B-factory and tau-charm factory. The CEPC will have two interaction points where two large detectors wil...

Hidden sector particles with sub-GeV masses like hidden U(1) gauge bosons, the NMSSM CP-odd Higgs, and other axion-like particles are experimentally little constrained as they interact only very weakly with the visible sector. For masses below the muon threshold, we present constraints from meson decays, g-2 as well as beam-dump and reactor experiments. The NMSSM CP-odd Higgs and generally any pseudoscalar is required to be heavier than 210 MeV or couple to fermions much weaker than the SM Higgs. Hidden photons are less constrained and can be searched for at future fixed-target experiments, e.g. HIPS at DESY. Hidden sectors are frequently proposed as part of the physics beyond the standard model. Since their interactions with the visible sectors are very weak, so are the current experimental bounds. In fact, motivated both from a bottom-up and a top-down perspective, those sectors might even contain light particles with masses in the sub-GeV range that have so far escaped detection. Among those weakly interacting slim particles (WISPs) are hidden U(1) gauge bosons, the CP-odd Higgs of the NMSSM, and other axion-like particles (ALPs). Such particles are of great interest in many models that seek to interpret recent terrestrial and astrophysical anomalies in terms of dark matter (DM). The rise in the positron-fraction with energy as observed by PAMELA (cf. ) and the deviation from the power-law in the e + + e -spectrum measured by FERMI (cf. [2]) together with the absence of an excess in antiprotons require the DM candidate to annihilate dominantly into leptons (leptophil) with a cross section much larger than the one giving the correct relic abundance. Different direct detection measurements like the annual modulation observed by DAMA/LIBRA [3] and the null results of CDMS and XENON [4, seem somewhat contradicting. Consistency might still be possible if either the DM candidate is light (m ∼ 5 -10 GeV) with elastic scattering or heavy with excited states (mass splitting ∆m ∼ 100 keV) generating inelastic scattering. Those properties are challenging for standard DM candidates and alternative scenarios like hidden sectors with light messenger particles have been considered because of the following advantageous features. A long range attractive force mediated by such a light messenger generates a so called Sommerfeld enhancement of the annihilation cross section. Dark matter annihilation proceeding through this messenger -if light enough -is naturally leptophilic due to kinematics. Inelastic scattering on nuclei can also be mediated by such a light particle. Possible examples of messenger particles that have already been studied are ALPs like the NMSSM CP-odd Higgs [6] and hidden U(1) photons of a generic hidden sector or of asymmetric mirror worlds . From a top-down perspective, hidden sectors appear naturally in various supersymmetric models descending from string theory. Mediator particles are generally weakly coupled to the

During the normal operation of a linear collider, while the beam are in collisions, the detuning of the final focus optics must be controlled in such a way that the luminosity stays maximum. The required on-line tuning procedure should be the least invasive in order to lose the least ...